Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
General Information: General Description
Communication between smart key PCM has 2 phase that is IG ON and Engine ON.
After this first IG ON transition phase or starting phase, a communication between Smart Key PCM and Engine PCM takes place.
- IG ON Phase (FOB key or Fob Key in Fob holder)
- Communication between Smart key PCM starts from wake-up signal from PCM.
- After receiving wake-up signal from PCM, Smart Key PCM sends lock or unlock starting signal to PCM.
- Starting Phase (FOB key or FOB key in Fob Holder)
- In case driver tries to start engine, although Engine PCM is locked status for starting at IG ON, Engine PCM should send re-authentication to Smart Key PCM. According to the results of re-authentication, it would be decided to start engine or not.
The Engine PCM controls the engine, in a normal way for starting and running, and start communication with the Smart Key PCM, sending a PIN request to the Smart Key PCM and waiting for valid release message from it until the release time period has ended.
In case of Smart Key PCM immobilizer function is locked, the Smart Key PCM answer is the no release message. Engine PCM enters in the locked state, which causes the activation of the immobilization actions of the engine.
In case of Smart Key PCM immobilizer function state is released, the Smart Key PCM answer is the release message, including the information Smart Key PCM in learnt mode and the PIN code.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.