Refer to Diagnostic System Check - Theft Deterrent in Theft Deterrent.
Circuit Description
The Vehicle Theft Deterrent (VTD) module is located within the steering column. The VTD system prevents the vehicle from cranking and starting if a valid ignition key signal is not received by the VTD module. Once the proper ignition key signal is received by the VTD module, a continue fuel enable password is sent to the PCM via class 2 serial data. The PCM monitors the state of health serial data message from the theft deterrent system to ensure that the PCM - VTD module 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 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 VTD module and already allowed fuel during the ignition cycle. The engine will not start or crank 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.
Conditions for Setting the DTC
| • | The VTD system has allowed fuel delivery. |
| • | 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 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:
Important: Several VTD system diagnostic procedures may call for disconnecting the VTD module 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 diagnostic work.
| • | Intermittent short circuit on the serial data circuit. Refer to Data Link Communications System Check in Wiring Systems and check all related wiring for an intermittent short to ground or short to voltage. |
| • | Poor Connection. Inspect the PCM and VTD module harness and related 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. Check for an intermittent short or open circuit in the wiring harnesses related to the VTD module, including the ignition, battery feed, ground, and serial data circuits. Refer to Wiring Repairs . |
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.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic System Check performed? | -- | ||
2 |
Important: If a loss of DLC data has already been diagnosed using the DLC Diagnosis table, clear this DTC and continue diagnosis with the Powertrain On Board Diagnostic (OBD) System Check . Attempt to select Vehicle Theft Deterrent (VTD) system data with the scan tool. Can Vehicle Theft Deterrent system data be displayed? | -- | ||
3 |
Was a problem found? | -- | ||
4 |
Was a problem found? | -- | Go to Diagnostic Aids. | |
5 |
Was a problem found? | -- | ||
6 |
Does the vehicle start and continue to run? | -- | System OK |
