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 00: Engine Control Unit Performance - No Additional Information

DTC B1000 31: Engine Control Unit Performance - General Checksum Error

DTC B1000 57: Engine Control Unit Performance - Expected Reaction After Event Did Not Occur

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 in all of the modules except the sensing and diagnostic module (SDM), when the ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.
    • If the code is set in the SDM it will never clear and the Air Bag indicator will remain illuminated.

Reference Information

Schematic Reference

Data Communication Schematics

Connector End View Reference

Data Communication Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

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.

Control Module References for control module replacement, setup, and programming