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

P1C8F-POWER SUPPLY 1 CIRCUIT HIGH

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


The Powertrain Control Module (PCM) has two ASD 12 Volt supply circuits which provide power to three input circuits at the PCM C2 connector. The (F342) circuit supplies power to pins one and three. The (F344) circuit supplies power to pin five. The PCM internally monitors the voltage supply at each circuit. If the PCM sees power on one of the circuits and not the other, it performs a diagnostic check of the circuit and sets a DTC. The circuits are linked internally so that if one of the circuits is found to be open (I.E. (F342) circuit), current from the (F344) circuit will transfer over to the (F342) circuit.



Possible Causes

CHARGING SYSTEM OUTPUT VOLTAGE HIGH
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


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 CHARGING SYSTEM OPERATION


1. (Refer to 08 - Electrical/8F - Engine Systems/Charging - Diagnosis and Testing) and perform the CHARGING SYSTEM diagnostic procedure.


Were any problems found?

Yes


No