For 1990-2009 cars

### Circuit Description

The powertrain control module (PCM) controls the fuel injector operation based on a vehicle theft deterrent (VTD) password from the vehicle body control module (BCM). When the ignition is first turned ON, the BCM sends a programmed theft deterrent password to the PCM. The PCM acknowledges the password and responds to the BCM that normal fuel injector operation will continue. When starting the engine, the PCM looks for a password from the BCM through the Class 2 serial data circuit. If the password is not recognized or not present, the PCM will disable the engine. If an incorrect or no password is received, this indicates that the engine will start and stall immediately. The Security indicator will flash on the instrument panel cluster (IPC) for approximately 4 seconds. If an incorrect or disable password is received more than three times, this indicates that the engine is disabled for at least 10 minutes and that the Security indicator will illuminate solid on the IPC for approximately 3 seconds then flash on the IPC for 10 minutes. If the PCM loses communication with the BCM within the same ignition cycle, the vehicle will be enter fail-enable mode and continue to run on the following ignition cycles.

### Conditions for Running the DTC

The ignition is cycled to ON.

### Conditions for Setting the DTC

• | The PCM receives a fuel disabled password from the BCM.

| Or

• | An undecided password was sent from the BCM.

### Action Taken When the DTC Sets

• | The PCM will record operating conditions at the time during which the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.

• | The fuel system is disabled by the PCM.

### Conditions for Clearing the MIL/DTC

• | A history DTC will clear after 40 consecutive warm up cycles without a fault.

• | A scan tool can clear current and history DTCs.

### Diagnostic Aids

Attempting to start the vehicle by bypassing the Passlock system or by substituting parts without performing the Programming Theft Deterrent System Components procedure may set a DTC P1631 and a P1632.

If no password is received, a DTC U1064 and P1632 may be set.

### Test Description

The number below refers to the step number on the diagnostic table.

1. The scan tool displays the actual voltage code sent from the Passlock cylinder. This voltage should be within 0-5 volts. If it is not, a theft deterrent B code will be set and should be diagnosed first.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform A Diagnostic System Check-Theft Deterrent? | Go to Step 2 | Go to Diagnostic System Check - Theft Deterrent
2 |

1. Install a scan tool.
2. Turn ON the ignition with the engine OFF.
3. Select the Display DTCs function for the PCM.

Does the scan tool display DTC P1626 or DTC P1631?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3 |

1. Perform the Programming Theft Deterrent System Components Procedure. Refer to Programming Theft Deterrent System Components .
2. Attempt to start the engine.

Does the engine start and continue to run?

Go to Step 8

Go to Step 4

4 |

1. Display the Security Data list for the BCM.
2. Observe the PASSLOCK DATA VOLTAGE parameter.

Does the scan tool indicate that the Passlock™ Data voltage is within 0-5 volts?

Go to Step 5

Go to Step 6

5 | Important: When replacing the PCM, perform the programming procedure. Refer to Powertrain Control Module Programming in Engine Controls 2.2L or Powertrain Control Module Programming in Engine Controls 3.4L. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls 2.2L or Powertrain Control Module Replacement in Engine Controls 3.4L.

Did you complete the replacement?

Go to Step 8

--

6 | Invalid data will set a theft deterrent B code. Refer to Diagnostic Trouble Code (DTC) List . Are there any theft deterrent B-codes set? | Go to Diagnostic Trouble Code (DTC) List | Go to Step 7
7 | Important: When replacing the BCM, perform the setup procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System. Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 8 | --
8 |

1. Using the scan tool, clear the DTCs.
2. Start the engine.
3. Idle the engine at the normal operating temperature.

Does the DTC reset?

System OK

Go to Step 2