No BCM Bus Message

NOTE: The code is active as soon as the condition is detected and is stored when the ignition is switched OFF.

WHEN MONITORED: Continuously when the ignition is ON.

SET CONDITION: Air bag warning lamp status message from body computer to cluster is not received by ACM once within 2 seconds.

THEORY OF OPERATION:
The body controller drives all cluster read outs by sending bus messages to the cluster--including whether the airbag warning lamp is ON or OFF.

The ACM sends a warning lamp status message to the BCM and the BCM then sends a corresponding status message to the cluster.

The ACM monitors the CCD bus to verify that the BCM sends a lamp status message to the cluster.

If the ACM does not receive the BCM-to-cluster message, a "No BCM Bus Message" code will occur.

POSSIBLE CAUSES:
- Open or shorted CCD bus lines (may be viewed in stored codes once bus is repaired)
- Intermittent bus failure
- Faulty body control module

For diagnostic procedures see DIAGNOSTIC CHARTS/TEST 1A. 1A Testing System Function