P1626

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
The Vehicle Theft Deterrent system consists of the following components:
- Powertrain Control Module (PCM).
- Body Control Module (BCM).
- Ignition Lock and Key.

The Vehicle Theft Deterrent system is designed to disable vehicle operation if the incorrect key or starting procedure is used. The Body Control Module enables the crank circuit to the starter and sends a signal to the PCM if the correct key is being used. If the proper signal does not reach the PCM on the fuel enable circuit, the PCM will not pulse the injectors ON and thus not allow the vehicle to continue to operate, even if the crank circuit is bypassed. The proper signal is between 40-60 Hz and is measured using the DC scale on the DMM.

CONDITIONS FOR RUNNING THE DTC
The Engine is running or cranking.

CONDITIONS FOR SETTING THE DTC
- The PCM does not receive the correct signal from the Body Control Module.
- Condition present for less than 1.0 second.

ACTION TAKEN WHEN THE DTC SETS
- The PCM stores the DTC information into memory when the diagnostic runs and fails.
- The Malfunction Indicator Lamp (MIL) will not illuminate.
- The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.
- The engine starts and then stalls or the starter does not engage.

CONDITIONS FOR CLEARING THE MIL/DTC
- A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.
- The PCM battery voltage is interrupted. Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS
- Inspect the GAGE fuse for an open. The GAGE fuse open causes DTC P1626 to set. Refer to Electrical Diagnosis.
- If the engine starts and then stalls, the Body Control Module is not suppling the appropriate signal or the theft deterrent fuel enable circuit is open, shorted to a ground, or shorted to a voltage.
- Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the freeze frame and/or failure records data can help determine how many miles since the DTC set. The Fail counter and the Pass counter can also aid in determining how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that the PCM recorded. This will isolate when the DTC failed.
- For an intermittent condition, refer to Symptoms. Testing and Inspection

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. An engine that does not crank and a DTC P1626 is set, indicates that there is a theft deterrent system problem. An incorrect ignition key or an incorrect starting procedure causes a no crank condition.
For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 3561-A. Using this kit prevents damage to the harness connector terminals.
3. An engine that does not crank indicates there is a problem with the Body Control Module.
4. This step determines if the Powertrain Control Module is capable of sending a 5.0 volt signal to the BCM.
5. This step determines if the Body Control Module is capable of sending a signal to the PCM. The Body Control Module sends the PCM a 4060 Hz signal.
6. This step determines if the condition is intermittent. If the engine starts and continues to operate, you may have corrected the condition during diagnoses. Inspect all connections at the BCM and the PCM.