p2138/p1516 help. Bad pcm? Update
07-31-2012, 09:30 PM
#1
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p2138/p1516 help. Bad pcm? Update I have a supercharged 5.3 with a pcm out of an 06 Envoy. Have been having intermitent problems losing throttle and setting code p2138, also it will occasionally set a p1516 code and shut off the fuel pump. Tried new pedal and throttle body, no change. I went through the harness and load tested all wires from pedal to pcm and from pcm to throttlebody, tested good with no voltage drop. after testing I didn't have any problems for over a month, now this past weekend it is back and worse than ever. I am thinking bad pcm but still go back to the problem going away for a while after having the harness out. Anybody have any ideas, HELP. This combo is in the car in my avatar. UPDATE- Installed new pcm (tuned by TJ at Bakers) still having the same problem. I am lost, need some ideas.
Last edited by chad5.0; 08-23-2012 at 09:20 PM.
08-01-2012, 11:50 AM
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Does not seem to matter, might be driving at steady throttle and have it happen or just taking off from a stop. I can't seem to find one particular time or action that causes it.
08-29-2012, 04:29 PM
#7
This may help you out follow the associated trouble tree after you perform the below tests.
TECHNICAL
Bulletin No.: 07-06-04-019D
Date: June 28, 2010
Subject: Intermittent Malfunction Indicator Lamp (MIL) Illuminated, DTC P2138 with Reduced Engine Power (Repair Instrument Panel (IP) to Body Harness Connector)
Models:
2005-2011 GM Passenger Cars and Light Duty Trucks (Including Saturn)
2005-2009 HUMMER H2
2006-2010 HUMMER H3
2005-2009 Saab 9-7X
Supercede:
This bulletin is being revised to update the model years and warranty information. Please discard Corporate Bulletin Number 07-06-04-019C (Section 06 - Engine/Propulsion System)
Condition
- Some customers may comment on an intermittent malfunction indicator lamp (MIL) being Illuminated with a message or an indicator that displays Reduced Engine Power.
- The technician may observe on a scan tool DTC P2138 - Accelerator Pedal Position (APP) Sensor 1-2 Correlation set as Current or in History.
Cause
This condition may be caused by water intrusion into the instrument panel (IP) to body harness connector, which carries the APP sensor signals to the ECM/PCM. This water intrusion results in a voltage difference between APP Sensor 1 and APP Sensor 2 that exceeds a predetermined value for more than a calibrated period of time, setting P2138.
Correction
Note
Aftermarket equipment can generate DTC P2138 and/or other DTCs.
1. Verify that aftermarket equipment is not electrically connected to any of the APP sensor signal or low reference circuits or to any other ECM/PCM 5V reference or low reference circuits. Refer to Checking Aftermarket Accessories in SI.
2. Perform the Diagnostic System Check - Vehicle.
¤ If any 5V reference DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
¤ If any 5V reference DTCs are not set, proceed to Step 3.
3. Locate the IP to body harness connector, which may be located in and around the left hand kick panel area or inside the IP. Depending on the vehicle and model year, refer to Wiring Systems or Power and Signal Distribution in SI.
Note
Some examples of potential water leaks are: A-pillar seals, sunroof drain lines (if equipped) and windshield/cowl sealing.
4. Inspect for a water leak in the area. If necessary use a water hose to determine the source of the leak. Refer to General Information > Water Leaks in SI.
¤ If a water leak is observed, repair as necessary. Verify the effectiveness of the repair.
5. Inspect the IP to body harness connector terminals for corrosion and debris. Refer to Testing for Intermittent Conditions and Poor Connections in SI.
¤ If any corrosion and/or debris is observed, repair as necessary.
6. After completing the repair, verify the proper operation of the system. Depending on the vehicle and model year, perform the Diagnostic Repair Verification procedure or refer to Diagnostic Trouble Code (DTC) List - Vehicle in SI.
Warranty Information (excluding Saab U.S. Models)
For vehicles repaired under warranty, use the appropriate labor operation for the source of the water leak
Warranty Information (Saab U.S. Models)
For vehicles repaired under warranty, use the table.
Disclaimer
TECHNICAL
Bulletin No.: 07-06-04-019D
Date: June 28, 2010
Subject: Intermittent Malfunction Indicator Lamp (MIL) Illuminated, DTC P2138 with Reduced Engine Power (Repair Instrument Panel (IP) to Body Harness Connector)
Models:
2005-2011 GM Passenger Cars and Light Duty Trucks (Including Saturn)
2005-2009 HUMMER H2
2006-2010 HUMMER H3
2005-2009 Saab 9-7X
Supercede:
This bulletin is being revised to update the model years and warranty information. Please discard Corporate Bulletin Number 07-06-04-019C (Section 06 - Engine/Propulsion System)
Condition
- Some customers may comment on an intermittent malfunction indicator lamp (MIL) being Illuminated with a message or an indicator that displays Reduced Engine Power.
- The technician may observe on a scan tool DTC P2138 - Accelerator Pedal Position (APP) Sensor 1-2 Correlation set as Current or in History.
Cause
This condition may be caused by water intrusion into the instrument panel (IP) to body harness connector, which carries the APP sensor signals to the ECM/PCM. This water intrusion results in a voltage difference between APP Sensor 1 and APP Sensor 2 that exceeds a predetermined value for more than a calibrated period of time, setting P2138.
Correction
Note
Aftermarket equipment can generate DTC P2138 and/or other DTCs.
1. Verify that aftermarket equipment is not electrically connected to any of the APP sensor signal or low reference circuits or to any other ECM/PCM 5V reference or low reference circuits. Refer to Checking Aftermarket Accessories in SI.
2. Perform the Diagnostic System Check - Vehicle.
¤ If any 5V reference DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
¤ If any 5V reference DTCs are not set, proceed to Step 3.
3. Locate the IP to body harness connector, which may be located in and around the left hand kick panel area or inside the IP. Depending on the vehicle and model year, refer to Wiring Systems or Power and Signal Distribution in SI.
Note
Some examples of potential water leaks are: A-pillar seals, sunroof drain lines (if equipped) and windshield/cowl sealing.
4. Inspect for a water leak in the area. If necessary use a water hose to determine the source of the leak. Refer to General Information > Water Leaks in SI.
¤ If a water leak is observed, repair as necessary. Verify the effectiveness of the repair.
5. Inspect the IP to body harness connector terminals for corrosion and debris. Refer to Testing for Intermittent Conditions and Poor Connections in SI.
¤ If any corrosion and/or debris is observed, repair as necessary.
6. After completing the repair, verify the proper operation of the system. Depending on the vehicle and model year, perform the Diagnostic Repair Verification procedure or refer to Diagnostic Trouble Code (DTC) List - Vehicle in SI.
Warranty Information (excluding Saab U.S. Models)
For vehicles repaired under warranty, use the appropriate labor operation for the source of the water leak
Warranty Information (Saab U.S. Models)
For vehicles repaired under warranty, use the table.
Disclaimer
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08-31-2012, 04:45 PM
#8
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P2138's suck! If you have good terminal tension at the throttle body, APP, and ECM, check the build date of the ECM. Look under the bar code and count over 9 digits. The 9th digit is the year of build and the next 3 are the day of the year. If between 5182 and 5304, there were internal problems with the ECM boards, and you will have to find another one. No, I don't know what the actual problem was.
If the ECM is out of the julian date range and the terminal tension is good at the connectors ( you should consider borrowing the terminal tools or get the correct terminals on a test wire to act as a feeler gauge), make sure there is no EMI source around or in the harness, or just route the throttle harness away from everything.
Soldered wires screw up this system! That is all I can think of, one repeat P2138 I had did take a new harness to fix.
You might inspect all the connector pins for evidence of fretting, corrosion or other damage if there is no water damage.
If the ECM is out of the julian date range and the terminal tension is good at the connectors ( you should consider borrowing the terminal tools or get the correct terminals on a test wire to act as a feeler gauge), make sure there is no EMI source around or in the harness, or just route the throttle harness away from everything.
Soldered wires screw up this system! That is all I can think of, one repeat P2138 I had did take a new harness to fix.
You might inspect all the connector pins for evidence of fretting, corrosion or other damage if there is no water damage.
04-22-2013, 10:03 AM
#9
I know this is an old thread but I had the same problem for a long time and I finally got it figured out. I originally had the battery ground on the passenger side head and the ecm ground on the driver's side. So I ran a ground strap to the other head but I still would get the P2138 code. I then realized the ecm case was touching the sheet metal in my engine bay. I isolated the ecm and the problem disappeared. I am now a firm believer that ground loops cause major problems especially when retrofitting these newer electronics.
