For 1990-2009 cars

### Circuit Description

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 engine control module (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.

### Conditions for Setting the DTC

DTC P1630 will set if the ECM is ready to learn a new password when:

• | The ECM had received an incorrect password.

• | The ECM finished the 10 minute learn pending timer, leaving the ignition switch ON for 10 minutes.

DTC P1630 diagnostic runs continuously when the above conditions have been met.

DTC P1630 is a type D DTC.

### Diagnostic Aids

Diagnose any BCM Passlock DTCs or communication DTCs first.

This DTC indicates the ECM received an incorrect password and learn mode is enabled.

The Passlock sensor, and ECM contain the same Passlock codes. If any of these components are replaced, a relearn procedure must be performed.