Issues with the throttle position sensor on a vehicle are usually pretty easy to diagnose, but sometimes you have to dig deeper to find the issue. Follow this Real Fix to see how the problem with this Spark’s throttle control was diagnosed and repaired.
Vehicle
2013 Chevrolet Spark LS 1.2L
Title
P2135, Replaced Throttle Body Wiring Harness
Complaint
The customer states the check engine light is on.
Cause
Connected a scan tool and found code P2135 – Throttle Position (TP) Sensor 1-2 Correlation. Performed a road test with the scan tool connected and found the signal parameter from the throttle body was erratic and had dropouts. Performed a visual inspection of the throttle body electrical connector, terminals and wiring harness and found with the engine idling, wiggled the wiring harness at the throttle body electrical connector and the engine idle became erratic. Disconnected the connector from the throttle body for inspection and found the wiring harness was dry rotted. Opened the insulation and found the wires were corroded and the wires were exposed. These test results verified the throttle body wiring harness was faulty.
Correction
Replaced the throttle body wiring harness, cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.