No Throttle Response, Rough Running and No DTCs - Possible TCM Concern - keywords APP engine idle inoperative misfire miss plate power reduced TCM
| Subject: | No Throttle Response, Rough Running, and No DTC - Possible TCM Concern |
| Models: | 2005 Saturn Ion |
| with 2.2L Engine (VIN F - RPO L61) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
On rare occasions, it may be noted that the engine runs rough intermittently while the transmission is in park and no DTCs will be present. If the accelerator pedal is pressed at this time while watching the APP and TP angles, it will be noted that the APP sensor angle increases normally but the TP angle does not increase with it.
Recommendation/Instructions:
If the SI diagnostics do not isolate a cause for this concern, monitor the brake switch parameters in Transmission Data and Cruise Control Data while pressing and releasing the brake pedal. If the brake switch inputs are not accurate when pressing and releasing the brake pedal, use SI to diagnose the inaccurate brake switch input and repair as necessary. If normal brake switch operation is noted, replace the TCM (Transmission Control Module).
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
