The Passlock system is designed to prevent vehicle theft by allowing the engine control module (ECM) 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 ECM. When the ignition is turned to the CRANK position, the BCM will look for a correct voltage code from the Passlock sensor. If the correct voltage code is not received within a certain amount of time or is incorrect, the BCM will send a fuel disable password to the ECM over the controller area network (CAN) link. The SECURITY telltale will flash and the engine will not be allowed to start. If the BCM receives the correct voltage code from the Passlock sensor that it has stored in memory, it will send a password over the CAN link to the ECM. If the ECM Passlock password stored in memory does not match the BCM password, or if the ECM receives an undecided password from the BCM, it will not allow the engine to start, or allow it to start then stall, within 4 seconds. The SECURITY telltale will flash for 10 minutes if the ECM receives an undecided, incorrect, or fuel disable password. If the password to the ECM is correct, the engine will operate normally. The password is sent continuously by the BCM to the ECM 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.

DTC P1632 will set if the ECM 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 D DTC.

Diagnose any BCM Passlock DTCs or communication DTCs first.

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

Perform the security system, Passlock, relearn procedure.