| Table 1: | Normal Device Power Moding |
| Table 2: | Code Setting Criteria (Fault) for Device Power Moding |
Circuit Description
Class 2 communications will not start until the vehicle systems "on" power mode has been identified. Three discrete wires from the ignition switch contacts are monitored by the instrument cluster (IPC) in order to determine the present power mode ignition switch position. The IPC communicates the system power mode to all class 2 modules on the class 2 serial data line.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1440 Power Mode Master Input Circuits Mismatch
Conditions for Running the DTC
The IPC must be powered.
Conditions for Setting the DTC
One of the 3 monitored ignition switch circuits has malfunctioned.
Action Taken When the DTC Sets
The IPC implements default actions for each ignition switch position when faults are detected.
Conditions for Clearing the DTC
The power moding malfunction must be corrected and then the code can be cleared by using the scan tool. The code also clears after 100 ignition cycles.
Key Position | ACC | IGN 1 | IGN 0 | Engine Running | Power Mode |
|---|---|---|---|---|---|
OFF | Inactive | Inactive | Inactive | No | OFF or RAP |
ACC | Active | Inactive | Inactive | No | ACC |
UNLOCK | Inactive | Inactive | Active | No | UNLOCK or RAP |
CRANK | Inactive | Active | Active | No | CRANK |
RUN | Active | Active | Active | No | RUN |
RUN | Active | Active | Active | Yes | RUN |
ACC | IGN 1 | IGN 0 | Engine Running | Power Mode (Default) |
|---|---|---|---|---|
Inactive | Active | Inactive | No | OFF or RAP |
Inactive | Active | Inactive | Yes | RUN |
Active | Active | Inactive | No | RUN |
Active | Active | Inactive | Yes | RUN |
Inactive | Active | Active | Yes | RUN (Fault is set only if this condition exists for more than 1 minute) |
Active | Inactive | Inactive | Yes | RUN |
Active | Inactive | Active | Yes | RUN |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Instrument Cluster Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool display near Battery Voltage for both parameters? | Go to Step 3 | Go to Step 4 |
3 |
Does the scan tool display Battery Voltage? | Go to Step 5 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
4 | Test the inactive ignition voltage circuit for an open, a high resistance, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 8 | Go to Step 6 |
5 | Test the ignition 1 voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 8 | Go to Step 6 |
6 | 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 8 | Go to Step 7 |
7 | 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 8 | -- |
8 |
Does the DTC reset? | Go to Step 2 | System OK |
