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 31: Engine Control Unit Performance - General Checksum Error

DTC B1000 33: Electronic Control Unit (ECU) Performance Special Memory Failure

DTC B1000 34: Electronic Control Unit (ECU) Performance RAM Failure

DTC B1000 35: Electronic Control Unit (ECU) Performance ROM Failure

DTC B1000 36: Electronic Control Unit (ECU) Performance EEPROM Failure

DTC B1000 37: Electronic Control Unit (ECU) Performance Watchdog

DTC B1000 39: Electronic Control Unit (ECU) Performance Internal Electronic Failure

DTC B1000 5A: Electronic Control Unit (ECU) Performance Plausibility Failure

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

Component 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

Control Module References for scan tool information

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