B1438
CIRCUIT DESCRIPTIONThe instrument cluster (IPC) supplies 54 volts to the instrument panel integration module (IPM) for operation of the HVAC vacuum fluorescent (VF) display. The IPC performs a diagnostic test on the 54 V VF display supply every 100 milliseconds.
CONDITIONS FOR RUNNING THE DTC
^ The battery voltage is greater than 9 volts.
^ The 54 V VF display supply is active.
CONDITIONS FOR SETTING THE DTC
The current draw by the IPM on the 54 V 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 IPC continues to check the circuit for a reduction in current draw.
^ After 2.5 seconds, the IPC disables the 54 V VF display supply.
CONDITIONS FOR CLEARING THE DTC
^ Current DTC
- During the recovery diagnostic mode, the current draw by the IPM on the 54 V 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.
TEST
