GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The body control module (BCM) produces the theft deterrent crank relay and fuel enable signal when ignition is ON and the proper ignition code voltage value is detected. The powertrain control module (PCM) monitors the fuel enable signal during crank. If the proper signal is present on the Class 2 Serial Data Circuit, the PCM enables the fuel delivery in order to allow the engine to start. If the PCM determines that the fuel enable signal is not present or incorrect while the engine is running, DTC P1626 is set. The engine continues to start and run as long as DTC P1626 is stored. If the problem affects inputs to the VTD signal, the starter motor may be disabled.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The PCM has detected a loss of the state of health serial data message from the theft deterrent system.

Action Taken When the DTC Sets

    • The powertrain control module (PCM) will not illuminate the malfunction indicator lamp (MIL).
    • The PCM will store conditions which were present when the DTC set as failure records data only. This information will not be stored as freeze frame data.

Conditions for Clearing the DTC

    • A history DTC will clear after 40 consecutive warm-up cycles have occured without a malfunction.
    • The DTC can be cleared by using a scan tool.

Step

Action

Yes

No

Schematic Reference: Theft Deterrent System Schematics

1

Did you perform the Theft Deterrent Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Theft Deterrent

2

Important: DTC P1626 can only be set along with a corresponding theft deterrent B-code. Refer to the DTC list in order to diagnose the appropriate theft deterrent B-code.

Is DTC P1626 set as a current DTC?

Go to Diagnostic Trouble Code (DTC) List

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems