2014 Jeep Wrangler JK Factory Service Manual 28 - DTC-Based Diagnostics

P2123-ACCELERATOR PEDAL POSITION SENSOR 1 CIRCUIT HIGH

For a complete wiring diagram, refer to the Wiring Information.


Theory of Operation

The Accelerator Pedal Position (APP) Sensor contains two independent three wire sensors. Each sensor provides independent pedal position signals to the PCM. The raw voltage signal from APP Sensor 1 is twice the raw voltage signal from APP Sensor 2. Although the raw voltage signals differ, the scan tool converts and displays these voltages as matching percentages of pedal travel.



Possible Causes

(K855) APP SENSOR 1 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
(K23) APP SENSOR 1 SIGNAL CIRCUIT SHORTED TO VOLTAGE
(K23) APP SENSOR 1 SIGNAL CIRCUIT SHORTED TO THE (K855) APP SENSOR 1 5-VOLT SUPPLY CIRCUIT OR (K856) APP SENSOR 2 5-VOLT SUPPLY CIRCUIT
(K167) APP SENSOR 1 SENSOR GROUND CIRCUIT OPEN/HIGH RESISTANCE
ACCELERATOR PEDAL POSITION SENSOR
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).


1. DTC IS ACTIVE



NOTE: If any Sensor Reference DTCs are present, perform the applicable diagnostic procedure for that DTC before continuing with this test.

NOTE: The APP Sensor 2 signal should always be approximately half the voltage of the APP Sensor 1 signal.
1. Ignition on, engine not running.
2. With the scan tool, select View DTCs.


Is the status Active for this DTC?

Yes


No


2. CHECK THE (K23) APP SENSOR 1 SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the APP Sensor harness connector.
3. Disconnect the PCM C2 harness connector.
4. Remove the ASD Relay from the TIPM.
5. Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay Connector.
6. Turn the ignition on.
7. Measure the voltage of the (K23) APP Sensor 1 Signal circuit at the APP Sensor harness connector.


Is there any voltage present?

Yes


No


3. CHECK THE (K23) APP SENSOR 1 SIGNAL CIRCUIT FOR A SHORT TO THE 5-VOLT SUPPLY CIRCUITS
1. Turn the ignition off.
2. Remove the jumper wire and install the ASD Relay.
3. Measure the resistance between the (K23) APP Sensor 1 Signal circuit and the (K855) APP Sensor 1 5-Volt Supply circuit in the APP Sensor harness connector.
4. Measure the resistance between the (K23) APP Sensor 1 Signal circuit and the (K856) APP Sensor 2 5-Volt Supply circuit in the APP Sensor harness connector.


Is the resistance above 10k Ohms for both of the circuits?

Yes


No


4. CHECK THE (K167) APP SENSOR 1 SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K167) APP Sensor 1 Sensor Ground circuit between the APP Sensor harness connector and the PCM C2 harness connector.


Is the resistance below 5.0 Ohms?

Yes


No


5. ACCELERATOR PEDAL POSITION SENSOR
1. Reconnect the APP Sensor harness connector.
2. Reconnect the PCM C2 harness connector.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Turn the ignition off.
6. Disconnect the APP Sensor harness connector.
7. Connect a jumper wire between the (K167) APP Sensor 1 Sensor Ground circuit and the (K23) APP Sensor 1 Signal circuit at the APP Sensor harness connector.
8. Turn the ignition on.
9. With the scan tool, select View DTCs.


NOTE: The scan tool should display an Accelerator Pedal Position Sensor 1 Low DTC as active with the jumper wire in place.


Does the scan tool display the DTC as described above?

Yes


No


6. POWERTRAIN CONTROL MODULE

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Accelerator Pedal Position Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Perform any Technical Service Bulletins that may apply.


Were any problems found?

Yes


No