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 body control module (BCM) send a class to message to the instrument panel cluster (IPC) to illuminate the SECURITY indicator. |
| • | 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 occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Theft Deterrent Diagnostic System Check? | Go to Step 2 | |
2 |
Important: If a loss of DLC data has already been diagnosed, clear this DTC and continue diagnosis with Diagnostic System Check - Engine Controls in Engine Controls - 5.7L. Is DTC P1631 set as a current code? | Go to Step 3 | |
3 | Inspect for poor connections at the harness connector of the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 5 | Go to Step 4 |
4 |
Important: The replacement powertrain control module (PCM) must be programmed. Refer to Programming Theft Deterrent System Components . Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 5.7L. Did you complete the replacement? | Go to Step 5 | -- |
5 |
Does the DTC reset? | Go to Step 2 | System OK |
