For 1990-2009 cars

### Circuit Description

DTC B1558 is an internal Body Control Module (BCM) fault.

### Conditions for Setting the DTC

The checksum is tested once on wake-up. The fault is set if the running checksum does not match the computed checksum.

### Action Taken When the DTC Sets

Stores a DTC B1558 in the BCM memory.

### Conditions for Clearing the DTC

• | The conditions for the fault are no longer present.

• | The use of a scan tool.

• | A history DTC will clear after 50 consecutive ignition cycles if the condition for the fault is no longer present.

### Diagnostic Aids

Perform the following steps:

1. Use a scan tool to clear the DTC.
2. Cycle the ignition switch.
3. If DTC B1558 is still current, replace the BCM.