For 1990-2009 cars

The passlock system is designed to prevent vehicle theft by allowing the PCM to disable the fuel injectors unless a correct key (voltage) code from the passlock sensor via the mechanical key is correct. The passlock system utilizes 4 components: the lock cylinder, passlock sensor, body control module (BCM), and powertrain control module (PCM). When the engine is cranked, the BCM will look for a password from the passlock sensor. If the password is not received within a certain amount of time or is incorrect, the BCM will send a "fuel disable password" to the PCM over the Class II link. The SECURITY telltale will flash and the engine will not be allowed to start. If the BCM receives the correct password from the passlock sensor that it has stored in memory, it will send it over the Class II link to the PCM. If the PCM passlock password it has stored in memory does not match the BCM password, or if the PCM receives an undecided password from the BCM, it will allow the engine to start then stall within 4 seconds. The SECURITY telltale will flash for 10 minutes if the PCM receives an undecided, incorrect, or fuel disable password. If the password to the PCM is correct, the engine will operate normally. The password is sent continuously by the BCM to the PCM during run mode. If the password becomes lost or incorrect during the drive cycle, the vehicle will be allowed to start on succeeding ignition cycles without the aid of passlock and the SECURITY telltale will be ON steady. This mode is called fail enable mode.

### Conditions for Setting the DTC

DTC P1632 will set if the PCM receives a fuel disable password or an undecided password from the BCM.

DTC P1632 diagnostic runs once per ignition cycle during engine crank.

DTC P1632 is a type C DTC.

### Diagnostic Aids

If the BCM/ECM/CRUISE/ABS 10 amp in UHFB opens, the engine will start then stall and DTC P1632 will be set.

If the BCM 15 amp fuse in UHFB opens, the engine will start then stall. DTC P1632, U1000, and/or U1064 will be set.

Diagnose any BCM passlock DTCs or communication DTCs first.

If the PCM receives an undecided password from the BCM during an engine crank, the engine will start then stall. If the PCM receives a fuel disable password, the engine will not start.

Important: The passlock sensor, BCM, and PCM contain the same passlock codes. If any of these components are replaced, a relearn procedure must be performed.

Perform the Security System (Passlock) Relearn Procedure.