Tac Issues (throttle body)
11-02-2010 | 09:36 PM
#1
Tac Issues (throttle body) UPDATE AT BOTTOM OF POST
I just bought a Vette a week ago and am having intermittant issues with a no start condition. Saturday nite I went out to the car and it wouldnt start, all gauges would cycle, relays and throttle body and fuel pump cycled, but starter would not engauge. At the time I did not have a scanner, nor did I know the exact steps on the DIC retrieval.
After 30 mins the car started up fine, and I cut it off and started it another 5 times that nite (happened at 11pm sat) with out any issues. Drove all day sunday (75 miles) and monday (10 miles) to work and it started every time. On Monday when trying to go home, car would not start and I had my Laptop with HPtuners with me.
Found-
P1516- TAC module actuator position performance
P1517- electronic throttle module
P1518- electronic throttle to pcm communication
Codes would not clear, car would not engauge starter.
(along with an ABS code and some AC actuator codes from before hand- history codes)
U1040 loss of abs/tcs communications
B0361 motor 1 feedback short
B0441 LH mix motor out of range
C1232 Left front wheel speed sensor circuit open or shorted
P1571 Traction control torque request circuit
P1689 Traction control delivered torque output circuit.
Started checking connectors and wires, found that the car had a n2o system previously at sometime. (had a few spliced into wires, had a WOT switch, and could see that a bottle had been mounted in the hatch area.) After 45 mins of messing and checking it, the car randomly started up. I took it home and parked it in the garage and starting repairing the wires.
I removed all the extra wires and splices, being sure to isolate and seal each splic correctly. I used liquid electrical tape on the bare wires, allowed that to dry, then used regular electrical tape to cover the liquid electrical tape and about 1/2 inch on either side. Once that was covered, I then taped that wire to 1 or 2 wires to secure it from moving. I ended up doing that to 5 wires. 2 under the dash, above the fuse box in the passenger floor board. 2 on the harness for the PCM, the connector that is on the outside of the vehicle. And 1 wire on the TPS.
After doing all of that, and looking over all the other visable wires for any signs of damage, or areas that do not appear stock, the car still will not start. I am hoping for some more insight as to what my next step should be in tracking this down.
2002 Z06 17k miles
Mod's:
Long tubes, unknown brand or size
off road mid pipes
factory Ti mufflers
G5x2 cam and springs
MSD wires
Cone style airfilter
tune.
ADDED
Just got home from work a min ago, and went out to see if the car would start. It did, first attempt.
Last nite all I did was remove and seal the slices, nothing else. The car would not start last nite or this morning at all, but tonite it did. Any ideas?
UPDATE
After dealing with this for some time, I had a cam lobe failure. I ended up putting a replacement engine in with a FAST 92 and a LS2 throttle body. I no longer have this issue. Thus, I can fairly confidently say that my issue was in the ported throttle body, either in the port job or the TAC moduel itself.
I just bought a Vette a week ago and am having intermittant issues with a no start condition. Saturday nite I went out to the car and it wouldnt start, all gauges would cycle, relays and throttle body and fuel pump cycled, but starter would not engauge. At the time I did not have a scanner, nor did I know the exact steps on the DIC retrieval.
After 30 mins the car started up fine, and I cut it off and started it another 5 times that nite (happened at 11pm sat) with out any issues. Drove all day sunday (75 miles) and monday (10 miles) to work and it started every time. On Monday when trying to go home, car would not start and I had my Laptop with HPtuners with me.
Found-
P1516- TAC module actuator position performance
P1517- electronic throttle module
P1518- electronic throttle to pcm communication
Codes would not clear, car would not engauge starter.
(along with an ABS code and some AC actuator codes from before hand- history codes)
U1040 loss of abs/tcs communications
B0361 motor 1 feedback short
B0441 LH mix motor out of range
C1232 Left front wheel speed sensor circuit open or shorted
P1571 Traction control torque request circuit
P1689 Traction control delivered torque output circuit.
Started checking connectors and wires, found that the car had a n2o system previously at sometime. (had a few spliced into wires, had a WOT switch, and could see that a bottle had been mounted in the hatch area.) After 45 mins of messing and checking it, the car randomly started up. I took it home and parked it in the garage and starting repairing the wires.
I removed all the extra wires and splices, being sure to isolate and seal each splic correctly. I used liquid electrical tape on the bare wires, allowed that to dry, then used regular electrical tape to cover the liquid electrical tape and about 1/2 inch on either side. Once that was covered, I then taped that wire to 1 or 2 wires to secure it from moving. I ended up doing that to 5 wires. 2 under the dash, above the fuse box in the passenger floor board. 2 on the harness for the PCM, the connector that is on the outside of the vehicle. And 1 wire on the TPS.
After doing all of that, and looking over all the other visable wires for any signs of damage, or areas that do not appear stock, the car still will not start. I am hoping for some more insight as to what my next step should be in tracking this down.
2002 Z06 17k miles
Mod's:
Long tubes, unknown brand or size
off road mid pipes
factory Ti mufflers
G5x2 cam and springs
MSD wires
Cone style airfilter
tune.
ADDED
Just got home from work a min ago, and went out to see if the car would start. It did, first attempt.
Last nite all I did was remove and seal the slices, nothing else. The car would not start last nite or this morning at all, but tonite it did. Any ideas?
UPDATE
After dealing with this for some time, I had a cam lobe failure. I ended up putting a replacement engine in with a FAST 92 and a LS2 throttle body. I no longer have this issue. Thus, I can fairly confidently say that my issue was in the ported throttle body, either in the port job or the TAC moduel itself.
Last edited by sabastian458; 05-21-2012 at 12:02 PM.
11-05-2010 | 11:11 AM
#6
car will not start, vehicle will not engauge starter when those 3 codes (p1516, p1517, p1518) The codes will not reset or clear out with hptuner scanner. Car will set for 1 to 2 days and then will start up like there was not problems at all (with no changes by me, not touching anything)
I have someone letting me borrow their Tech2 with CANDI module so I can get into the various control modules. I also purchased a LS2 throttle body (should be here next week) incase the TAC module on the LS1 throttle body is indeed bad.
I have someone letting me borrow their Tech2 with CANDI module so I can get into the various control modules. I also purchased a LS2 throttle body (should be here next week) incase the TAC module on the LS1 throttle body is indeed bad.
11-05-2010 | 05:11 PM
#7
To help those who may have the same issues as I.
P1518
CIRCUIT DESCRIPTION
The throttle actuator control (TAC) module and the powertrain control module (PCM) communicate via a dedicated serial data circuit. This serial data circuit is separate from any other serial data circuit on the vehicle. Accurate transmitting and receiving of serial data requires not only good circuit integrity, but also adequate system voltage. This diagnostic monitors the accuracy of the serial data transmitted between the TAC module and the PCM. If the PCM detects a loss of data or invalid data, this DTC sets.
CONDITIONS FOR RUNNING THE DTC
The ignition switch is in the crank or the run position.
The ignition voltage is greater than 5.23 volts .
CONDITIONS FOR SETTING THE DTC
Invalid or missing serial data messages are detected for a predetermined amount of time.
All of the above conditions met for less than 1 second .
ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
The control module commands the TAC system to operate in the Reduced Engine Power mode.
OR
Under certain conditions the control module commands the engine OFF.
The message center displays Reduced Engine Power.
CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
DTC P1518 sets if the battery voltage is low. If the customer's concern is slow cranking or no crank because battery voltage is low, ignore DTC P1518. Clear any DTCs that may have set from the low battery voltage condition from the memory.
DTC P1518 sets when there is a short to B+ on the TAC module ground circuit. Inspect the fuses for the circuits that are in the TAC module harness, such as the cruise, or the brake. An inspection of the fuses may lead you to the circuit that is shorted to the TAC module ground circuit.
DTC P1518 sets if the TAC module ignition feed circuit is shorted to a B+ supply circuit. The TAC module stays powered-up when the ignition switch is turned off. When the ignition switch is turned on, the TAC module is powered-up before the PCM. DTC P1518 sets because no communication is detected by the TAC module from the PCM. Inspect related circuits for being shorted to a B+ supply circuit.
Inspect the TAC module power and ground circuits and the TAC module/PCM serial data circuits for intermittent connections.
Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing.
When the TAC module detects a problem within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual problem may correct more than 1 DTC. keep this in mind when reviewing captured DTC info.
For an intermittent condition, refer to Intermittent Conditions. See: Initial Inspection and Diagnostic Overview\Diagnostic Strategies\Intermittent Conditions
The numbers below refer to the step numbers on the diagnostic table.
This step determines if the IGN relay is supplying a voltage to the THROT CONT fuse.
Increasing the engine speed to 3,000 RPM aids in locating a shorted throttle actuator motor control circuit. Depending on the polarity of the throttle actuator motor transistors, this DTC may not set with a fault in the control circuits. The throttle actuator motor is a bi-directional DC motor. Raising the engine speed changes the polarity of the transistors in the throttle actuator motor. This occurs because 1 set of the transistors is near 0 volts , and the other set is at high B+. Therefore, if 1 set of transistors is at a low voltage and the corresponding circuit is shorted low, DTC P1518 will not set. When the polarity of the transistors change this DTC sets. If this DTC does not Fail This Ignition, continue to monitor this DTC status while moving related harnesses and connectors.
When the TAC module detects a condition within the TAC system, more than TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. keep this in mind when reviewing the stored information, Capture info
P1518
CIRCUIT DESCRIPTION
The throttle actuator control (TAC) module and the powertrain control module (PCM) communicate via a dedicated serial data circuit. This serial data circuit is separate from any other serial data circuit on the vehicle. Accurate transmitting and receiving of serial data requires not only good circuit integrity, but also adequate system voltage. This diagnostic monitors the accuracy of the serial data transmitted between the TAC module and the PCM. If the PCM detects a loss of data or invalid data, this DTC sets.
CONDITIONS FOR RUNNING THE DTC
The ignition switch is in the crank or the run position.
The ignition voltage is greater than 5.23 volts .
CONDITIONS FOR SETTING THE DTC
Invalid or missing serial data messages are detected for a predetermined amount of time.
All of the above conditions met for less than 1 second .
ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
The control module commands the TAC system to operate in the Reduced Engine Power mode.
OR
Under certain conditions the control module commands the engine OFF.
The message center displays Reduced Engine Power.
CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
DTC P1518 sets if the battery voltage is low. If the customer's concern is slow cranking or no crank because battery voltage is low, ignore DTC P1518. Clear any DTCs that may have set from the low battery voltage condition from the memory.
DTC P1518 sets when there is a short to B+ on the TAC module ground circuit. Inspect the fuses for the circuits that are in the TAC module harness, such as the cruise, or the brake. An inspection of the fuses may lead you to the circuit that is shorted to the TAC module ground circuit.
DTC P1518 sets if the TAC module ignition feed circuit is shorted to a B+ supply circuit. The TAC module stays powered-up when the ignition switch is turned off. When the ignition switch is turned on, the TAC module is powered-up before the PCM. DTC P1518 sets because no communication is detected by the TAC module from the PCM. Inspect related circuits for being shorted to a B+ supply circuit.
Inspect the TAC module power and ground circuits and the TAC module/PCM serial data circuits for intermittent connections.
Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing.
When the TAC module detects a problem within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual problem may correct more than 1 DTC. keep this in mind when reviewing captured DTC info.
For an intermittent condition, refer to Intermittent Conditions. See: Initial Inspection and Diagnostic Overview\Diagnostic Strategies\Intermittent Conditions
The numbers below refer to the step numbers on the diagnostic table.
This step determines if the IGN relay is supplying a voltage to the THROT CONT fuse.
Increasing the engine speed to 3,000 RPM aids in locating a shorted throttle actuator motor control circuit. Depending on the polarity of the throttle actuator motor transistors, this DTC may not set with a fault in the control circuits. The throttle actuator motor is a bi-directional DC motor. Raising the engine speed changes the polarity of the transistors in the throttle actuator motor. This occurs because 1 set of the transistors is near 0 volts , and the other set is at high B+. Therefore, if 1 set of transistors is at a low voltage and the corresponding circuit is shorted low, DTC P1518 will not set. When the polarity of the transistors change this DTC sets. If this DTC does not Fail This Ignition, continue to monitor this DTC status while moving related harnesses and connectors.
When the TAC module detects a condition within the TAC system, more than TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. keep this in mind when reviewing the stored information, Capture info
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11-05-2010 | 05:13 PM
#8
P1517
CIRCUIT DESCRIPTION
The throttle actuator control (TAC) module contains data which is essential for proper TAC system operation. The TAC module continuously tests the integrity of this data. When the TAC module is unable to write or read data to and from random access memory (RAM) or when the TAC module is unable to correctly read data from the flash memory, or when an internal TAC module processor fault is detected, this DTC sets.
CONDITIONS FOR RUNNING THE DTC
DTC P1518 is not set.
The ignition switch is in the crank or the run position.
The ignition voltage is greater than 6 volts .
CONDITIONS FOR SETTING THE DTC
The TAC module determines that an internal data test did not pass.
All above conditions met for less than 1 second .
ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
The control module commands the TAC system to operate in the Reduced Engine Power mode.
OR
Under certain conditions the control module commands the engine OFF.
The message center displays Reduced Engine Power.
CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
Ensure the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.
Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing.
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. keep this in mind when reviewing the stored information, Capture info.
The number below refers to the step number on the diagnostic table.
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. keep this in mind when reviewing the stored information, Capture info.
CIRCUIT DESCRIPTION
The throttle actuator control (TAC) module contains data which is essential for proper TAC system operation. The TAC module continuously tests the integrity of this data. When the TAC module is unable to write or read data to and from random access memory (RAM) or when the TAC module is unable to correctly read data from the flash memory, or when an internal TAC module processor fault is detected, this DTC sets.
CONDITIONS FOR RUNNING THE DTC
DTC P1518 is not set.
The ignition switch is in the crank or the run position.
The ignition voltage is greater than 6 volts .
CONDITIONS FOR SETTING THE DTC
The TAC module determines that an internal data test did not pass.
All above conditions met for less than 1 second .
ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
The control module commands the TAC system to operate in the Reduced Engine Power mode.
OR
Under certain conditions the control module commands the engine OFF.
The message center displays Reduced Engine Power.
CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
Ensure the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.
Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing.
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. keep this in mind when reviewing the stored information, Capture info.
The number below refers to the step number on the diagnostic table.
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. keep this in mind when reviewing the stored information, Capture info.
11-05-2010 | 05:14 PM
#9
P1516
CIRCUIT DESCRIPTION
The predicted throttle position, based on the accelerator pedal position and possibly on other limiting factors, is compared to the actual throttle position. The 2 values should be within a calibrated range of each other. Both the powertrain control module (PCM) and the throttle actuator control (TAC) module redundantly monitor the predicted and the actual throttle position. This DTC sets if the TAC detects an out of range condition between the predicted and the actual throttle position.
CONDITIONS FOR RUNNING THE DTC
DTC P1518 is not set.
The ignition switch is in the crank or the run position.
The ignition voltage is greater than 5.23 volts .
The TAC system is not in the battery saver mode.
CONDITIONS FOR SETTING THE DTC
The TAC module detects that the predicted and actual throttle positions are not within a calibrated range of each other.
OR The PCM and the TAC cannot determine throttle position.
OR Both throttle position (TP) sensors are invalid
All of the above conditions are met for less than 1 second .
ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
The control module commands the TAC system to operate in the Reduced Engine Power mode.
OR
Under certain conditions the control module commands the engine OFF.
The message center displays Reduced Engine Power.
CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing.
Ensure that the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture info.
For an intermittent, refer to Intermittent Conditions. See: Initial Inspection and Diagnostic Overview\Diagnostic Strategies\Intermittent Conditions
The numbers below refer to the step numbers on the diagnostic table.
If the TP Indicated angle does not follow the movement of the throttle blade, and no TP Sensor DTCs are set, there is a mechanical condition with the throttle shaft or the TP sensor.
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture info.
CIRCUIT DESCRIPTION
The predicted throttle position, based on the accelerator pedal position and possibly on other limiting factors, is compared to the actual throttle position. The 2 values should be within a calibrated range of each other. Both the powertrain control module (PCM) and the throttle actuator control (TAC) module redundantly monitor the predicted and the actual throttle position. This DTC sets if the TAC detects an out of range condition between the predicted and the actual throttle position.
CONDITIONS FOR RUNNING THE DTC
DTC P1518 is not set.
The ignition switch is in the crank or the run position.
The ignition voltage is greater than 5.23 volts .
The TAC system is not in the battery saver mode.
CONDITIONS FOR SETTING THE DTC
The TAC module detects that the predicted and actual throttle positions are not within a calibrated range of each other.
OR The PCM and the TAC cannot determine throttle position.
OR Both throttle position (TP) sensors are invalid
All of the above conditions are met for less than 1 second .
ACTION TAKEN WHEN THE DTC SETS
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
The control module commands the TAC system to operate in the Reduced Engine Power mode.
OR
Under certain conditions the control module commands the engine OFF.
The message center displays Reduced Engine Power.
CONDITIONS FOR CLEARING THE MIL/DTC
The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing.
Ensure that the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture info.
For an intermittent, refer to Intermittent Conditions. See: Initial Inspection and Diagnostic Overview\Diagnostic Strategies\Intermittent Conditions
The numbers below refer to the step numbers on the diagnostic table.
If the TP Indicated angle does not follow the movement of the throttle blade, and no TP Sensor DTCs are set, there is a mechanical condition with the throttle shaft or the TP sensor.
When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture info.
11-05-2010 | 09:16 PM
#10
welp, tried to drive to work this morning at 7am, nada, nothing, no start again. Left it in the garage and didnt fool with it and drove my ram. Came home and walked out and tried to start it at 8pm and it fired right up. I did nothing different, nothing changed, car did not move. WTF
11-05-2010 | 09:18 PM
#11
when it starts, it runs wonderfully. no check engine light. Idles great too. does have a small cam so it has small lope. Yes it has a drive by wire, with a seperate TPS.
11-09-2010 | 05:07 PM
#12
Quick update for anyone paying attention.
Yesterday morning, when attempting to start for the morning, it would not. I cycled the key several times and then just held it over in the start position for about 20+ seconds. Surprisingly it started up. Drove it to work (15mins or so) and started it several times in sucession without issue. No issues for the rest of the day.
THis morning same thing, no start first time in the morning. Cycled key a few times, then held in the start position for about 15+ sec and it fired up. Then when I left for lunch no start, cycled key 3 times and held in start position for about 10-15 sec and fired up.
When it startes and runs, no codes and no check engine light, drives fine.
Yesterday morning, when attempting to start for the morning, it would not. I cycled the key several times and then just held it over in the start position for about 20+ seconds. Surprisingly it started up. Drove it to work (15mins or so) and started it several times in sucession without issue. No issues for the rest of the day.
THis morning same thing, no start first time in the morning. Cycled key a few times, then held in the start position for about 15+ sec and it fired up. Then when I left for lunch no start, cycled key 3 times and held in start position for about 10-15 sec and fired up.
When it startes and runs, no codes and no check engine light, drives fine.
11-10-2010 | 09:32 AM
#13
FInally, some new information.
went to run an errand at work just a few mins ago. Car would not start, cycled key aprox 15 times, randomly holding in the start position for 10-15 secs. no start. Held over in start pos for aprox 25-30 and it fired up. The DIC said "pull key, wait 10 seconds" but did not display service column lock.
Looked in the stickies and found this thread;
http://forums.corvetteforum.com/c5-t...ky-please.html
and it says this
So what should I do now? Get a new key? or delete VATS from the ECU?
went to run an errand at work just a few mins ago. Car would not start, cycled key aprox 15 times, randomly holding in the start position for 10-15 secs. no start. Held over in start pos for aprox 25-30 and it fired up. The DIC said "pull key, wait 10 seconds" but did not display service column lock.
Looked in the stickies and found this thread;
http://forums.corvetteforum.com/c5-t...ky-please.html
and it says this
A6 If you get the "Pull Key and Wait 10 Seconds" message but no "Service Column Lock" message, it can sometimes be a symptom of your security system and related to your key pellet.
11-30-2010 | 12:11 PM
#15
Sorry I havent updated this thread along with the other one from corvetteforum.
Update:
I did the ignition switch repair I found on here, cleaning the contact points in the electrical side of the switch. 2 of the contacts had basically turned all blackened, and 2 others had slight black marks. Cleaned all of them, and bent the tabs for more contact pressure. I also installed the CLB kit too.
It didnt fix it, but it seemed to help a little. My next step is finish cleaning all the ground points and then running dedicated ground wires from the negitive battery terminal to all the factory ground points.
Oh, no codes present when it is running. When it doesnt start, the only codes are the P1516, P1517, P1518. Once it starts, those codes go away.
I have no idea why it will start after a period of time. I had thought that the ignition switch was causing that, as the contacts did have signs of burnt but since I cleaned them all up and adjusted the tension on them it still has the same issues.
My next step is to begin to start removing the factory grounding connectors and replace them with proper eyelet terminals and heat shrink, and then run a dedicated, proper ground wire from each of the factory ground points to the negitive battery terminal.
After the first of the year I have had plans to removed the LS6 in lew of my LS2 setup that I have and install a new clutch, and was planing on cleaning everything and checking all the connectors for the engine at that time as well. I will get this problem tracked down and murdered, it annoys the crap out of me.
Update:
I did the ignition switch repair I found on here, cleaning the contact points in the electrical side of the switch. 2 of the contacts had basically turned all blackened, and 2 others had slight black marks. Cleaned all of them, and bent the tabs for more contact pressure. I also installed the CLB kit too.
It didnt fix it, but it seemed to help a little. My next step is finish cleaning all the ground points and then running dedicated ground wires from the negitive battery terminal to all the factory ground points.
Oh, no codes present when it is running. When it doesnt start, the only codes are the P1516, P1517, P1518. Once it starts, those codes go away.
I have no idea why it will start after a period of time. I had thought that the ignition switch was causing that, as the contacts did have signs of burnt but since I cleaned them all up and adjusted the tension on them it still has the same issues.
My next step is to begin to start removing the factory grounding connectors and replace them with proper eyelet terminals and heat shrink, and then run a dedicated, proper ground wire from each of the factory ground points to the negitive battery terminal.
After the first of the year I have had plans to removed the LS6 in lew of my LS2 setup that I have and install a new clutch, and was planing on cleaning everything and checking all the connectors for the engine at that time as well. I will get this problem tracked down and murdered, it annoys the crap out of me.
04-20-2012 | 11:03 AM
#16
Hey, just as an update to those who may have similar issues.
Not too much longer after my last post I had a cam lobe wipe issue. I pulled the LS6 and put my LS2 in as was my plan, just sooner than I wanted. In doing so I installed a LS2 90 mm throttle body. Since getting the car back running, there have NOT been any more issues or codes for the TAC system.
So in conclusion to this issue, I am 98% confident that it was a failed/shorted TAC module on the throttle body.
Not too much longer after my last post I had a cam lobe wipe issue. I pulled the LS6 and put my LS2 in as was my plan, just sooner than I wanted. In doing so I installed a LS2 90 mm throttle body. Since getting the car back running, there have NOT been any more issues or codes for the TAC system.
So in conclusion to this issue, I am 98% confident that it was a failed/shorted TAC module on the throttle body.
04-30-2012 | 09:18 AM
#18
05-20-2012 | 09:22 PM
#19
TECH Enthusiast
Joined: Dec 2005
Posts: 530
Likes: 0
From: Owasso,Ok/Honolulu, HI
Did you ever get just the p1516 codes with your issue? I am getting this code on occasion with p1278 and I just installed a FAST 102/102 setup on my 03 Z06. The car goes into REP when I get the p1278 code, then once and awhile the p1516 will show up. TIA
05-21-2012 | 10:11 AM
#20
I would start there first, then check the ground points in the area of the intake, and then check to make sure you did not pinch any wires when bolting things back down.