B1438

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The instrument cluster (IPC) supplies power (54 volts) to the instrument panel integration module (IPM) for operation of the HVAC vacuum fluorescent (VF) display.

CONDITIONS FOR RUNNING THE DTC
^ The battery voltage is greater than 9 volts.
^ The 54 V VF display supply is active.
^ The IPC performs a diagnostic test on the 54V VF display supply every 100 milliseconds.

CONDITIONS FOR SETTING THE DTC
The current draw by the IPM on the 54V VF display supply circuit is greater than 100 milliamps for 5 diagnostic tests.

ACTION TAKEN WHEN THE DTC SETS
^ For 2.5 seconds, the IPC enters recovery diagnostic mode. The PC continues to check the circuit for a reduction in current draw.
^ After 2.5 seconds, the PC disables the 54V VF display supply.

CONDITIONS FOR CLEARING THE DTC
^ Current DTC
- During the recovery diagnostic mode, the current draw by the IPM on the 54V VF display supply circuit is less than 95 milliamps for 5 diagnostic tests.
- The ignition is OFF.
^ History DTC
- A scan tool is used.
- The IPC automatically clears the history DTC when a current DTC is not detected for 50 consecutive ignition cycles.

DIAGNOSTIC AIDS
^ An intermittent condition can be caused by the following:
- The wiring harness is routed incorrectly.
- The insulation of the wiring is rubbed through.
^ Following successful diagnosis, cycle the ignition so that initialization of the circuit occurs.

For a description of the RPO Code(s) shown in this image/article refer to the RPO Code List found at Vehicle/Application ID RPO Codes