Chevy Trax in Limp Mode, MIL On
Nov. 08 2022
Nov. 08 2022

Vehicle: 2015 Chevy Trax, AWD, L4-1.4L Turbo

Mileage: 68, 994

Problem: This vehicle was towed in because the truck has no throttle response, no power and bucked and jerked on acceleration.

Case Details: The technician pulled diagnostic trouble code (DTC) P2138 - Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage. He checked technical service bulletins (TSBs) in ALLDATA and found TSB 07-06-04-019G. It said to check for signs of water around the APP sensor harness. The sensor harness was dry and showed no signs of water damage. The technician replaced the APP sensor but that did not fix the problem.

An ALLDATA Tech-Assist consultant advised him that when the voltage in this type of circuit goes high, check the ground wire first because it may be an open circuit. The wiring diagram showed APP2 ground wire was black/violet (BLK/VIO). He also recommended testing the APP2 5-volt reference wire. It was brown/red (BRN/RED).

Chevy Trax Diagram

The tech found 5-volts on the BRN/RED wire but no ground at the APP harness for APP2 on the BLK/VIO wire. The PCM side of the harness showed good ground, so the wire between the PCM and APP was open somewhere.

The technician traced the harness and found connector X112 under the battery was damaged. (NOTE: Connector X112 location - #3 in the image).

Battery acid leaked on the connector and ruined the BLK/VIO ground wire. The insulation was missing.

Confirmed Repair: The technician overlayed the BLK/VIO ground wire to bypass the connector, cleaned the connector and the rest of the pins, cleared the DTC and test drove the vehicle. Problem solved!

The ALLDATA Tech-Assist team fields cases like this every day. See how Tech-Assist can help your shop save time and money with on-call diagnostic support from ASE-certified Master Technicians. More Tech Tips 

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