Pinpoint Test J : App (Accelerator Pedal Position) Faults: Notes

WARNING: This page is about a different variant/trim than selected.

Refer to Electronic Engine Controls for schematic and connector information.

Normal Operation and Fault Conditions

There are 2 APP signals in the sensor. Both signals, APP 1 and APP 2, have a positive slope (increasing angle, increasing voltage), but are offset and increase at different rates. The 2 APP signals make sure the PCM receives a correct input even if 1 signal has a concern. The PCM determines if a signal is incorrect by calculating where it should be, inferred from the other signals. If a concern is present with one of the circuits the other input is used. There are 2 reference voltage circuits, 2 signal return circuits, and two signal circuits (a total of 6 circuits and terminals) between the PCM and the APP sensor assembly. The APP signal is converted to pedal travel degrees (rotary angle) by the PCM. The software then converts these degrees to counts, which is the input to the torque based strategy. The PCM sets a DTC if voltage on these inputs are above or below a calibrated threshold.

Possible Sources

Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
APP sensor
PCM

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Conditions
P0120:12	Throttle/Pedal Position Sensor "A" Circuit Short to Battery	The PCM detects the APP sensor 1 signal is to high.
P0120:14	Throttle/Pedal Position Sensor "A" Circuit Short to Ground or Open	The PCM detects the APP sensor 1 signal is to low or open.
P0220:12	Throttle/Pedal Position Sensor "B" Circuit Short to Battery	The PCM detects the APP sensor 2 signal is to high.
P0220:14	Throttle/Pedal Position Sensor "B" Circuit Short to Ground or Open	The PCM detects the APP sensor 2 signal is to low or open.
P2122:14	Throttle/Pedal Position Sensor/Switch "D" Circuit Low	The PCM detects the APP sensor 1 is out of self-test range low.
P2123:12	Throttle/Pedal Position Sensor/Switch "D" Circuit High	The PCM detects the APP sensor 1 is out of self-test range high.
P2127:14	Throttle/Pedal Position Sensor/Switch "E" Circuit Low	The PCM detects the APP sensor 2 is out of self-test range low.
P2128:12	Throttle/Pedal Position Sensor/Switch "E" Circuit High	The PCM detects the APP sensor 2 is out of self-test range high.
P2135:1F	Throttle/Pedal Position Sensor/Switch "A"/" B" Voltage Correlation	The PCM detects a concern indicating that APP voltage PIDs APP 1 and APP 2 disagree by more than a calibrated limit.
P2138:1F	Throttle/Pedal Position Sensor/Switch "D"/" E" Voltage Correlation	The PCM compares the APP 1 and APP 2 sensor inputs. This DTC sets when the APP sensor 1 and APP 2 inputs disagree on the position of the accelerator pedal by more than an expected value.