Circuit Description
The instrument panel cluster (IPC) supplies 54 volts to the instrument panel module (IPM) for operation of the HVAC vacuum fluorescent (VF) display. The IPC performs a diagnostic test on the 54V VF display supply every 100 milliseconds.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1438 IPC High Voltage Output Overcurrent to CCP
Conditions for Running the DTC
| • | The battery voltage is greater than 9 volts. |
| • | The 54V VF display supply is active. |
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 IPC continues to check the circuit for a reduction in current draw. |
| • | After 2.5 seconds, the IPC disables the 54V VF display supply. |
Conditions for Clearing the 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.
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. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Interior Lights Dimming Schematics Connector End View Reference: Lighting Systems Connector End Views , Computer/Integrating Systems Connector End Views in Computer/Integrating Systems, or Instrument Panel, Gages, and Console Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Test the 54V VF display supply circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 5 | Go to Step 3 |
3 | Inspect for poor connections at the harness connector of the instrument panel cluster (IPC). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 5 | Go to Step 4 |
4 | Replace the IPC. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 5 | -- |
5 |
Does the DTC Reset? | Go to Step 2 | System OK |
