P1626

Refer to Theft Deterrent System Schematics in Accessories and Optional Equipment / Antitheft and Alarm Systems / Diagrams.

Circuit Description

The Vehicle Theft Deterrent (VTD) system is incorporated within the Body Control Module (BCM). The PCM monitors the state of health serial data message from the VTD system to ensure that the PCM to BCM communications is established. If the PCM detects a loss of the state of health message while the engine is running, DTC P1626 will be set. DTC P1626 can cause a no-start condition or normal operation depending on when the loss of VTD system communication was detected. The engine will continue to start and run if the condition that set DTC P1626 occurred after the PCM received a valid VTD password from the BCM and already allowed fuel during the ignition cycle. The engine will start and immediately stall if the condition that set DTC P1626 occurred before the PCM received a valid VTD password. With this condition present, the PCM will inhibit fuel delivery and disable the starter until a valid VTD password is detected. Refer to Content Theft Deterrent (CTD) Circuit Description, and Vehicle Theft Deterrent (VTD) Operation in Antitheft and Alarm Systems.

Conditions for Running the DTC

The VTD system has allowed fuel delivery.

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

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

Diagnostic Aids

Check for the following conditions:

Important: Several BCM diagnostic procedures call for disconnecting the BCM and then turning the vehicle ignition to the RUN position. These procedures will result in the PCM setting DTC P1626. Therefore, DTC P1626 stored in history may be the result of previous BCM diagnostic work.

Intermittent short circuit on the serial data circuit. Refer to A Diagnostic System Check - Data Link Communications in Data Link Connector / Testing and Inspection. Be sure to check all related wiring for an intermittent short to ground or short to voltage.

Important: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection.
Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Diagrams.
^ Damaged harness.
Inspect the wiring harness for damage. If the harness appears to be OK, observe the sensor display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the sensor display may indicate the location of the fault.
^ Inspect the PCM and the engine grounds for clean and secure connections.

If the DTC is determined to be intermittent, reviewing the Fail Records can be useful in determining when the DTC was last set.