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 Descriptor

DTC B1013: Calibration Read Only Memory (ROM) Checksum Error

Circuit/System Description

The control module runs a program to detect an internal fault when power up is commanded. The module retains a copy of the FLASH application checksum reference value in the FLASH memory. During wake-up the module will compute the FLASH application value and compare it to the FLASH application checksum reference value.

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

FLASH application value does not match checksum reference value.

Action Taken When the DTC Sets

The module may have limited functional operation depending on the severity of the FLASH calibration corruption.

Conditions for Clearing the DTC

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

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 B1013 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