Fault code index · medium
P1123
APP Sensor sense circuit high voltage – APP1 Note: This DTC could be flagged by both sensor eleme…
APP Sensor sense circuit high voltage – APP1 Note: This DTC could be flagged by both sensor element sensing circuit having faults.
Scope: 2.5L/3.0L gasoline · System(s): EMS OBD II · Factory MIL flag: 2 · Default action: ECM Default: –APP angle default value used –Speed control inhibited –APP adaptions (wear, variance) inhibited
Common causes
- APP Sensor sensor to ECM sense circuit(s) (APP1 or APP2): short circuit to B+ voltage APP Sensor sensor ground circuit(s): open circuit APP Sensor failure
Quick checks
- Confirm freeze-frame and conditions when the code set
- Inspect connectors, grounds, and harness for the circuit named in the code
- Compare live sensor values vs expected (unplugged/biased sensors are common)