GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    •  Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B1000: Electronic Control Unit (ECU) Performance

Circuit/System Description

The control module runs a program to detect an internal fault when power up is commanded.

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

The control module has detected an internal malfunction.

Action Taken When the DTC Sets

The control module refuses all additional inputs.

Conditions for Clearing the DTC

    • A current DTC clears when the malfunction is no longer present.
    • A history DTC clears when the ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Circuit/System Verification

Verify that DTC B1000 is not set.

If the DTC is set, perform the setup procedure on the control module. If the DTC resets replace the control module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  SIR/SRS Wiring Repairs
    •  Control Module References for control module replacement, setup, and programming