P1626

Diagnostic Chart:

Wiring Diagram:

Circuit Description

The Theft Deterrent system is incorporated within the Body Control Module (BCM). The PCM monitors the state of health serial data message from the Theft Deterrent 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 Theft Deterrent 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 Theft Deterrent password from the Body Control Module (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 password. With this condition present, the PCM will inhibit fuel delivery and disable the starter until a valid password is detected.

Conditions for Setting the DTC

^ The engine is running.

^ The PCM detects an incorrect Theft Deterrent Fuel Enable signal on the Class II circuit.

^ The above conditions are present for longer than 2 seconds.


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 the scan tool Clear Info function or by disconnecting the PCM battery feed.


Diagnostic Aids

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Check for:

^ Poor connection. Inspect the PCM and Theft Deterrent module harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

^ Damaged harness. Inspect the wiring harness for damage.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.