Incorrect Immobilizer Key
The PCM has detected a problem with the immobilizer key identification.
Code Set Parameters
The PCM, powertrain interface module (PIM), and the body control module (BCM) work together to authenticate the identity of the vehicle immobilizer key. If the key identity fails to comply with the identity of the key programmed for a particular vehicle, a code will be stored and a malfunction indicator lamp will be illuminated.
Symptoms may include a delayed or no start condition, an illuminated security lamp, a stored code, and an illuminated service engine soon lamp.
The most common cause of this code being stored is from using a theft deterrent key that is faulty or is not programmed for the vehicle. Technicians also report that ignition cylinder failure is also quite common. Electrical circuit malfunctions, electrical connector faults, and faulty modules are also possible.
The ignition cylinder is often replaced in error when the key itself is actually the culprit.
- The PCM, BCM, and PIM interact as integral parts of the vehicle security system
- The theft deterrent system authenticates security data received from these modules to prevent unauthorized vehicle operation
- The system is activated in the following procedure: When the door/s are unlocked using the hand held remote key fob or key, data is transferred to the BCM
- The BCM reads the data and makes sure that the correct key was used
- A similar action occurs when the ignition key is placed in the cylinder and turned
- The BCM examines the signal sent from the key and makes sure that it matches the vehicle
- Once the identity of the key has been verified, the identity of the PCM, BCM, and PIM are also verified
- If the key identity, PCM identity, BCM identity, and PIN identity are all verified, the engine is allowed to start
If any step of this process is interrupted by a component that is not identified correctly by the theft deterrent system, starting may be disabled and a code stored
Several tools will be instrumental in successfully diagnosing this code
- A suitable OBD-II scanner (or code reader) and a digital volt/ohmmeter will be most helpful in performing a successful diagnosis
Begin with a visual inspection of all wiring and connectors
- Repair or replace damaged, disconnected, shorted, or corroded wiring, connectors, and components as necessary
- Always retest the system after repairs are completed to ensure success.
If all system wiring, connectors, and components (Including fuses) appear to be in normal working order, connect the scanner (or code reader) to the diagnostic connector and record all stored codes and freeze frame data
- This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
- Continue by clearing the code and operating the vehicle to see if it returns
- This will help to determine whether or not the malfunction is intermittent
After the codes are cleared, test drive the vehicle to see if the code returns
- If the code fails to immediately return, you may have an intermittent condition
- Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made
If the code returns and/or the engine fails to start, turn the key to the key on engine off position and reset the code again
- If a second immobilizer key is available, attempt to start the engine using it
- If the engine starts and/or the code does not return, you have a faulty key
- Replace the key as necessary.
If the second key fails to start the engine, then follow the manufacturer’s recommendations for reprogramming the immobilizer key
- After completing this procedure, attempt to start the engine again.
If the engine fails to start, suspect a faulty ignition cylinder
- You may test circuit resistance in the ignition cylinder by inserting the key and comparing your actual findings with manufacturer’s specifications
- Replace the ignition cylinder as required, reset the code, and retest the system
If the ignition cylinder proves to be operational, disconnect the related modules and measure continuity in all circuits
- Compare your findings with the manufacturer’s specified tolerances and repair open or shorted circuits as needed