Circuit Description

BCM supplies a 5-volt signal and a ground circuit for PASS-Key(R) system. This allows BCM to detect PASS-Key(R) resistance values. Inserting PASS-Key(R) (with resistor pellet) into ignition lock cylinder completes PASS-Key(R) circuit. Contacts in ignition lock cylinder mate with pellet contacts. BCM compares resistance value of key pellet to valid resistance programmed into BCM. If proper resistance value is read, BCM allows the following functions to occur:

• Theft deterrent relay to energize.
• Steering column to unlock.
• BCM sends a message through serial data line to PCM to enable fuel delivery.

When BCM is replaced, new BCM must be programmed to accept resistance value of existing vehicle keys so that it will allow PASS-Key(R) operation. The new BCM is programmed to accept the first PASS-Key(R) resistance value detected.

If BCM is unable to detect a valid PASS-Key(R) resistance value, BCM will not end programming sequence and DTC B2735 will set. DTC B2735 will set when BCM is unable to detect a valid PASS-Key(R) code during BCM programming due to an open or short in PASS-Key(R) circuit.