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 provide an overview of each diagnostic category.

DTC Descriptor

DTC P0700: Transmission Control Module (TCM) Requested MIL Illumination

Circuit/System Description

This diagnostic trouble code (DTC) indicates that an emission related transmission DTC set in the transmission control module (TCM). The engine control module (ECM) receives the TCM information over the serial data circuit. The ECM turns ON the malfunction indicator lamp (MIL) when the TCM sends a message over the serial data circuit requesting MIL illumination. The DTC information for the ECM will only display DTC P0700, but the Freeze Frame/Failure Records data will display the transmission DTC that set.

Conditions for Running the DTC

    • The engine speed is greater than 512 RPM.
    • The engine run time is greater than 2.5 seconds.
    • The ignition voltage is greater than 9.03 volts.

Conditions for Setting the DTC

The TCM is requesting MIL illumination.

Action Taken When the DTC Sets

DTC P0700 is a Type A DTC.

Conditions for Clearing the DTC

DTC P0700 is a Type A DTC.

Circuit/System Verification

Important: Correct any Engine Controls DTCs before diagnosing TCM DTCs.

DTC P0700 is an informational DTC. If there are no Engine Controls DTCs, refer to Diagnostic Trouble Code (DTC) List - Vehicle for diagnosis of TCM DTCs.