B1372

DTC B1372

Circuit Description

Normal vehicle class 2 communication will not commence until the system power mode has been identified. The dash integration module (DIM) is the power mode master (PMM). The DIM communicates the system power mode to all the modules connected to the class 2 serial data circuit. The DIM monitors the state of the IGN 1 and Accessory voltage circuits in order to determine the present system power mode.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1372 Device Ignition 1 Circuit Low

Conditions for Running the DTC

Anytime the DIM receives an input or message.

Conditions for Setting the DTC

The DIM has detected the IGN 1 voltage circuit is low for greater than 1 minute when the Accessory voltage circuit is high and the engine run flag is true.

Action Taken When the DTC Sets

* DTC B1372 is set in the DIM.
* The malfunction indicator lamp (MIL) is illuminated.
* The DIM along with other modules on the class 2 serial data circuit, will execute the power mode backup strategy.

Conditions for Clearing the MIL/DTC

* A current DTC clears and the MIL is turned OFF when the fault is no longer present.
* A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the fault.

Diagnostic Aids

Refer to Testing for Intermittent Conditions and Poor Connections. Component Tests and General Diagnostics






Test Description

Step 1 - Step 11:

Step 12 - Step 16:

The numbers below refer to the step numbers on the diagnostic table.
6. This step tests for a short to battery voltage on the active signal circuit.
7. This step tests the inactive signal circuit for an open or a high resistance.
8. If any ignition switch parameters that should be inactive in the present ignition switch position are active, 2 ignition switch signal circuits may be shorted together.