Engine Code
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#9
Circuit/System Description
The throttle actuator control (TAC) system uses 2 throttle position (TP) sensors to monitor the throttle position. The TP sensors 1 and 2 are located within the throttle body assembly. Each sensor has the following circuits:
* A 5-volt reference circuit
* A low reference circuit
* A signal circuit
Two processors are also used to monitor the TAC system data. Both processors are located within the engine control module (ECM). Each signal circuit provides both processors with a signal voltage proportional to throttle plate movement. Both processors monitor each other's data to verify that the indicated TP calculation is correct.
Conditions for Running the DTC
P0120, P0122, P0123, P0220, P0222, and P0223
* DTC P0601, P0602, P0603, P0604, P0606, P0607, P0641, P0651 are not set.
* The system voltage is more than 5.23 volts.
* The ignition is in the Unlock/Accessory or Run position.
* DTC P0120, P0122, P0123, P0220, P0222, P0223 run continuously when the above conditions are met.
P2135
* The system voltage is more than 5.23 volts.
* The ignition is in the Unlock/Accessory or Run position.
* DTC P0120, P0220, P0641, P0651 are not set.
* DTC P2135 runs continuously when the above conditions are met.
Conditions for Setting the DTC
P0120
TP sensor 1 voltage is less than 0.325 volt or more than 4.75 volts for more than 1 second.
P0122
The ECM detects that the TP sensor 1 voltage is less than 0.325 volt for more than 1 second.
P0123
The ECM detects that the TP sensor 1 voltage is more than 4.75 volts for more than 1 second.
P0220
The TP sensor 2 voltage is less than 0.25 volt or more than 4.59 volts for more than 1 second.
P0222
The ECM detects that the TP sensor 2 voltage is less than 0.25 volt for more than 1 second.
P0223
The ECM detects that the TP sensor 2 voltage is more than 4.59 volts for more than 1 second.
P2135
The difference between the TP sensor 1 and TP sensor 2 exceeds a predetermined value for more than 2 seconds.
Action Taken When the DTC Sets
* DTC P0120, P0122, P0123, P0220, P0222, P0223, and P2135 are Type A DTCs.
* The control module commands the TAC system to operate in the Reduced Engine Power mode.
* A message center or an indicator displays Reduced Engine Power.
* Under certain conditions the control module commands the engine OFF.
Conditions for Clearing the MIL/DTC
DTCs P0120, P0122, P0123, P0220, P0222, P0223, and P2135 are Type A DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics
Description and Operation
Throttle Actuator Control (TAC) System Description
Connector End View Reference
* Engine Controls Connector End Views
* Engine Control Module Connector End Views
Electrical Information Reference
* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
* Scan Tool Data List
* Scan Tool Data Definitions
Circuit/System Verification
1. Ignition ON, observe the scan tool TP sensor 1 voltage parameter. The reading should be between 4.75–0.33 volts and change with accelerator pedal input.
2. Ignition ON, observe the scan tool TP sensor 2 voltage parameter. The reading should be between 0.25–4.59 volts and change with accelerator pedal input.
3. Ignition ON, observe the scan tool TP sensor 1 and 2 parameter. The scan tool should indicate agree.
4. Clear the DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC, or within the conditions that you observed from the Freeze Frame/Failure Records.
5. Verify that DTC P0120 or P0220 are not the only throttle position DTCs set.
⇒X If DTC P0120 or P0220 are the only DTCs set, replace the control module.
6. Verify that DTCs P0641 or P0651 are not set.
⇒X If DTC P0641 or P0651 is set, refer to DTC P0641 or P0651.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the throttle body. Allow up to 2 minutes for the ECM to completely power down.
2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal C and ground.
⇒X If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, test for 4.8–5.2 volts between 5-volt reference circuit terminal E and ground.
4. If less than 4.8 volts, test 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
6. Verify the scan tool TP sensor 1 voltage is less than 0.1 volt.
⇒X If greater than 0.1 volt, test the signal circuit terminal D for a short to voltage. if the circuit tests normal, replace the ECM.
7. verify the scan tool TP sensor 2 voltage is greater than 4.8 volts.
⇒X If less than 4.8 volts, test the signal circuit terminal F for a short to ground. If the circuit tests normal, replace the ECM.
8. Install a 3A fused jumper wire between the signal circuit terminal D and the 5-volt reference circuit terminal E of the TP sensor 1. Verify the TP sensor 1 voltage is greater than 4.8 volts.
⇒X If less than 4.8 volts, test the TP sensor 1 signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
9. Install a 3A fused jumper wire between the signal circuit terminal F and the low reference circuit terminal C of the TP sensor 2. Verify that the TP sensor 2 voltage is less than 0.1 volt.
⇒X If greater than 1.0 volt, test the TP sensor 2 signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
10. Ignition OFF, disconnect the harness connector at the ECM.
11. Test for less than 5 ohms of resistance on all TP sensor circuits between the following terminals:
* ECM C2 signal circuit terminal 65 to TP terminal D
* ECM C2 signal circuit terminal 63 to TP terminal F
* ECM C2 5-volt reference circuit terminal 3 to terminal E
⇒X If greater than 5 ohms, repair the affected circuit for open/high resistance.
12. Test for infinite resistance between TP sensor 1 signal circuit terminal D and TP sensor signal circuit terminal F.
⇒X If less than infinite resistance, repair the short between TP sensor 1 signal circuit and TP sensor 2 signal circuit.
13. If all circuits test normal, replace the throttle body.
The throttle actuator control (TAC) system uses 2 throttle position (TP) sensors to monitor the throttle position. The TP sensors 1 and 2 are located within the throttle body assembly. Each sensor has the following circuits:
* A 5-volt reference circuit
* A low reference circuit
* A signal circuit
Two processors are also used to monitor the TAC system data. Both processors are located within the engine control module (ECM). Each signal circuit provides both processors with a signal voltage proportional to throttle plate movement. Both processors monitor each other's data to verify that the indicated TP calculation is correct.
Conditions for Running the DTC
P0120, P0122, P0123, P0220, P0222, and P0223
* DTC P0601, P0602, P0603, P0604, P0606, P0607, P0641, P0651 are not set.
* The system voltage is more than 5.23 volts.
* The ignition is in the Unlock/Accessory or Run position.
* DTC P0120, P0122, P0123, P0220, P0222, P0223 run continuously when the above conditions are met.
P2135
* The system voltage is more than 5.23 volts.
* The ignition is in the Unlock/Accessory or Run position.
* DTC P0120, P0220, P0641, P0651 are not set.
* DTC P2135 runs continuously when the above conditions are met.
Conditions for Setting the DTC
P0120
TP sensor 1 voltage is less than 0.325 volt or more than 4.75 volts for more than 1 second.
P0122
The ECM detects that the TP sensor 1 voltage is less than 0.325 volt for more than 1 second.
P0123
The ECM detects that the TP sensor 1 voltage is more than 4.75 volts for more than 1 second.
P0220
The TP sensor 2 voltage is less than 0.25 volt or more than 4.59 volts for more than 1 second.
P0222
The ECM detects that the TP sensor 2 voltage is less than 0.25 volt for more than 1 second.
P0223
The ECM detects that the TP sensor 2 voltage is more than 4.59 volts for more than 1 second.
P2135
The difference between the TP sensor 1 and TP sensor 2 exceeds a predetermined value for more than 2 seconds.
Action Taken When the DTC Sets
* DTC P0120, P0122, P0123, P0220, P0222, P0223, and P2135 are Type A DTCs.
* The control module commands the TAC system to operate in the Reduced Engine Power mode.
* A message center or an indicator displays Reduced Engine Power.
* Under certain conditions the control module commands the engine OFF.
Conditions for Clearing the MIL/DTC
DTCs P0120, P0122, P0123, P0220, P0222, P0223, and P2135 are Type A DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics
Description and Operation
Throttle Actuator Control (TAC) System Description
Connector End View Reference
* Engine Controls Connector End Views
* Engine Control Module Connector End Views
Electrical Information Reference
* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
* Scan Tool Data List
* Scan Tool Data Definitions
Circuit/System Verification
1. Ignition ON, observe the scan tool TP sensor 1 voltage parameter. The reading should be between 4.75–0.33 volts and change with accelerator pedal input.
2. Ignition ON, observe the scan tool TP sensor 2 voltage parameter. The reading should be between 0.25–4.59 volts and change with accelerator pedal input.
3. Ignition ON, observe the scan tool TP sensor 1 and 2 parameter. The scan tool should indicate agree.
4. Clear the DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC, or within the conditions that you observed from the Freeze Frame/Failure Records.
5. Verify that DTC P0120 or P0220 are not the only throttle position DTCs set.
⇒X If DTC P0120 or P0220 are the only DTCs set, replace the control module.
6. Verify that DTCs P0641 or P0651 are not set.
⇒X If DTC P0641 or P0651 is set, refer to DTC P0641 or P0651.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the throttle body. Allow up to 2 minutes for the ECM to completely power down.
2. Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal C and ground.
⇒X If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, test for 4.8–5.2 volts between 5-volt reference circuit terminal E and ground.
4. If less than 4.8 volts, test 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
6. Verify the scan tool TP sensor 1 voltage is less than 0.1 volt.
⇒X If greater than 0.1 volt, test the signal circuit terminal D for a short to voltage. if the circuit tests normal, replace the ECM.
7. verify the scan tool TP sensor 2 voltage is greater than 4.8 volts.
⇒X If less than 4.8 volts, test the signal circuit terminal F for a short to ground. If the circuit tests normal, replace the ECM.
8. Install a 3A fused jumper wire between the signal circuit terminal D and the 5-volt reference circuit terminal E of the TP sensor 1. Verify the TP sensor 1 voltage is greater than 4.8 volts.
⇒X If less than 4.8 volts, test the TP sensor 1 signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
9. Install a 3A fused jumper wire between the signal circuit terminal F and the low reference circuit terminal C of the TP sensor 2. Verify that the TP sensor 2 voltage is less than 0.1 volt.
⇒X If greater than 1.0 volt, test the TP sensor 2 signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
10. Ignition OFF, disconnect the harness connector at the ECM.
11. Test for less than 5 ohms of resistance on all TP sensor circuits between the following terminals:
* ECM C2 signal circuit terminal 65 to TP terminal D
* ECM C2 signal circuit terminal 63 to TP terminal F
* ECM C2 5-volt reference circuit terminal 3 to terminal E
⇒X If greater than 5 ohms, repair the affected circuit for open/high resistance.
12. Test for infinite resistance between TP sensor 1 signal circuit terminal D and TP sensor signal circuit terminal F.
⇒X If less than infinite resistance, repair the short between TP sensor 1 signal circuit and TP sensor 2 signal circuit.
13. If all circuits test normal, replace the throttle body.
#13
before you do, i think somoene mentioned that you had cut wires on this car? were any of them to either of the TPS's? also, did you solder them properly, or did you crimp them in butt connectors?
the basic jist of that code is high resistance. something has to be causing it.
the basic jist of that code is high resistance. something has to be causing it.
#18
The throttle body has a TP1 and a TP2 sensor in it. One goes from 0-5V, the other from 5-0V. The ECM takes these two sensor values, adds them together and if they don't equal 5V(with a degree of error) there is a problem. ECM monitors each individual circuit as well.
Every GM throttle by wire circuits are set up like this because its needs to be dead nuts accurate, otherwise whose controlling that throttle?
Could be with the wires to the TB, the actual sensors inside the throttle body or the ECM.
Any kind of extra resistance in these circuits and problems arise, the sensitivity of the ECM to these circuits is around .2V.
I have seen butt connectors in these circuits cause this code, because when they get hot, they start to expand and the connections resistance creeps up and causes an issue.
Also, I have seen poor terminal tension on these circuits because the ECM side of the circuit has very small terminals(.64mm) which will spread out and cause intermittent connections. Seen similar terminal issues on the TB side too.
If its a real intermittent problem its gonna suck to diagnose but if you messed at all with the wiring, check that first.
Then I would look at the throttle body being your culprit.
Good luck!
Every GM throttle by wire circuits are set up like this because its needs to be dead nuts accurate, otherwise whose controlling that throttle?
Could be with the wires to the TB, the actual sensors inside the throttle body or the ECM.
Any kind of extra resistance in these circuits and problems arise, the sensitivity of the ECM to these circuits is around .2V.
I have seen butt connectors in these circuits cause this code, because when they get hot, they start to expand and the connections resistance creeps up and causes an issue.
Also, I have seen poor terminal tension on these circuits because the ECM side of the circuit has very small terminals(.64mm) which will spread out and cause intermittent connections. Seen similar terminal issues on the TB side too.
If its a real intermittent problem its gonna suck to diagnose but if you messed at all with the wiring, check that first.
Then I would look at the throttle body being your culprit.
Good luck!
#19
Thank you I appreciate your help.
We'll like I said, the plug that had to be extended because of the supercharger install which was just a plug to plug piggyback kinda system; so I didnt have to splice any wire. I was thinking if in your case you say it get's too hot, you'd think it would have done it on a hotter day than a 70degree day.
ive still been searching to see if those codes together p2135 and c2024 mean anything when they go off together. But have had no luck. Im gonna see if I can borrow someones LS2 TB so I dont have to buy one, since my V isnt my DD and I dont need to drive it if I dont have to
Anyone have one they arent using? : )
We'll like I said, the plug that had to be extended because of the supercharger install which was just a plug to plug piggyback kinda system; so I didnt have to splice any wire. I was thinking if in your case you say it get's too hot, you'd think it would have done it on a hotter day than a 70degree day.
ive still been searching to see if those codes together p2135 and c2024 mean anything when they go off together. But have had no luck. Im gonna see if I can borrow someones LS2 TB so I dont have to buy one, since my V isnt my DD and I dont need to drive it if I dont have to
Anyone have one they arent using? : )
#20
I realize this thread is almost 5 years but I also went into low power mode. I had just entered a highway and brought the speed up around 70 when it occurred. I also have a Maggie supercharger.