Immobilizer Anti-Theft System

The immobilizer antitheft system requires diagnosis when it is not possible to start the engine. If the no-start condition occurs because of the immobilizer system, a diagnostic trouble code (DTC) 53 should be set.
The immobilizer control unit monitors the detection and the reading of the ignition key. The selftest capacity is limited to those functions. Faults are communicated to a scan tool during diagnosis, but are not stored in the immobilizer control units memory.
Unauthorized use of a scan tool could be a method of defeating the immobilizer anti-theft system. Therefore, certain scan tool procedures require the use of a pass-word. The following functions are password protected:
- Coding of an additional key.
- Deleting all key codes.
- Deletion of the immobilizer identification (ID) code.
- Deletion of the powertrain control module (PCM)/engine control module (ECM) ID code.

The following functions do not require a password:
- Reading an ignition key to determine if the transponder is working or if a key is authorized.
- Reading the immobilizer ID code to verify that it matches the PCM/ECM ID code.

Steps 1 Thru 6:

DTC 53- PCM/ECM Immobilized Error