P38 alarm and immobilizer problems

feyniriel said:

Indeed! When the car started we looked at each other and said "damn, Datatek is always right". We got an offer by an electrician to disable the immobilizer for 250€ by sending him the ECU, turns out it was already disabled! So nothing could've fixed it except a Nanocom anyway.

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Turn off EKA so if the FOB fails you can use the key blade to operate the car.

Grrrrrr said:

Turn off EKA and passive immobilisation.

I think RF interference can cause it to lose sync although why it would is a mystery. Mine certainly did regularly until I fitted a generation 3 RF receiver.

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Maybe there's something in BECM that engages immobilisation after a certain number of bad RF messages, i.e. an LR work-around to not fixing the earlier receivers !

pwood999 said:

Maybe there's something in BECM that engages immobilisation after a certain number of bad RF messages, i.e. an LR work-around to not fixing the earlier receivers !

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There is actually no such thing as Immobilisation in the BECM, the BECM actually sends a Mobilisation code to activate the EDC when the ignition is turned on. The code in the EDC has a fixed value therefore the BECM sends a code of the same value to activate the EDC. What happens ether by design or accident, is that the code held in the BECM gets corrupted when repeated spurious FOB codes are received. The BECM continues to send the code even when it's not the correct code.