P1612 NISSAN - Chain of ECM-IMMU
- Faulty IMMU
- Faulty Engine Control Module (ECM)
If the problem occurs try disconnecting the car battery for about 30 minutes and then try starting the engine with a known registered key. If the problem persist you have to have the dealer erase the code and reprogram the keys again.
- Engine would not start
An immobilizer is an electronic device fitted to an automobile which prevents the engine from running unless the correct key is present. This prevents the car from being hot wired after entry has been achieved.
The microcircuit inside the key is activated by a small electromagnetic field which induces current to flow inside the key body, which in turn broadcasts a unique binary code which is read by the automobile's Engine Control Module (ECM). When the ECM determines that the coded key is both current and valid, the ECM activates the fuel-injection sequence.
The immobilizer function of the Nissan Vehicle Immobilizer System (NVIS) or Nissan Anti-Theft System (NATS) consists of the following:
- NATS ignition key
- NATS antenna amp. located in the ignition key cylinder
- Body control module (BCM) or (IMMU)
- Engine Control Module (ECM)
- Security indicator lamp