Circuit Description
The Body Control Module (BCM) produces the Theft Deterrent Fuel Enable signal when ignition is ON and the proper key resistor pellet is sensed. The PCM monitors the Fuel Enable signal during crank. If the proper signal is present on the Theft Deterrent Fuel Enable circuit, the PCM enables fuel delivery to allow the engine to start. If the PCM detects that the fuel enable signal is not present or incorrect 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 the fuel enable signal was detected. The engine will continue to start and run if the condition that set DTC P1626 occurred after the BCM sensed the proper key resistor pellet and signaled the PCM to continue fuel delivery. The engine will start and immediately stall if the condition that set DTC P1626 occurred before the BCM sensed the proper key resistor pellet. With this condition present, the PCM will inhibit fuel delivery and disable the starter. If the problem affects inputs to the BCM, the starter motor may be disabled. If this condition is present, refer to Vehicle Theft Deterrent System for further diagnosis.
Conditions for Setting the DTC
| • | The engine is running. |
| • | The PCM detects an incorrect signal on the Theft Deterrent Fuel Enable Circuit. |
| • | The condition is 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 Information 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 at PCM - Inspect harness connectors for the following items: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Poor terminal to wire connections |
| • | Damaged harness - Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the vehicle theft deterrent module, turn the ignition ON and observe a DMM connected to the theft deterrent fuel enable circuit at the vehicle theft deterrent module harness connector while moving connectors and wiring harnesses related to the vehicle theft deterrent system. A change in voltage will indicate the location of the malfunction. |
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.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
2 |
Important:: Before continuing diagnosis, ensure that the vehicle battery is fully charged. Attempt to start the engine. Does the engine crank? | -- | Go to Vehicle Theft Deterrant System. | |
3 |
Does the voltage measure near the specified value? | 5V | ||
4 |
Is the frequency between the specified values? | 40-60 Hz | ||
5 |
Does the vehicle start and continue running? | -- | Go to Diagnostic Aids | |
6 |
Was a problem found? | -- | ||
7 |
Was a problem found? | -- | ||
8 |
Was a problem found? | -- | ||
|
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM.Is action complete? | -- | -- | ||
10 | Service the body control module. Refer to BCM Service in section 8D. Is action complete? | -- | -- | |
11 |
Does VTD Fuel Disable display Active? | -- | System OK |
