I have had this peculiar problem since buying my Renault Master, 3 years ago.

The immobilizer usually works fine however if I park the van in the hot sun, when I try to start it, I get the immobilizer light flashing rapidly.

I have 2 keys and the same thing happens with both.

I have opened the immobilizer ring and cleaned the circuit with a brush but did not make any difference.

As a temporary solution, I have kept the ring outside the case and I move it closer to the top of the key (where the chip is), every time I get this issue.

Anyone experiencing the same thing?

What is the cheapest way to solve this issue? If I was to get another immobilizer ring case and swap my circuit for the one in it, would it make any difference?

  • 1
    I would bet replacement of the ring is going to be your best option. More than likely, since it happens when the inside of the car gets hot, something inside the ring expands and loses contact, which either makes its range much smaller or makes it so it doesn't want to work at all. These rings (no matter what make/model of car) can be fickle beasts. I'm not completely familiar with the Renault's ignition system, so leaving this as a comment. There could be other things at play here. Commented Jul 26, 2018 at 11:09
  • 1
    Are you saying with the immobilizer ring closer to the chip it works every time or does the problem persist? I’d get a wiring diagram for the immobilizer system and do some voltage drop and signal testing before pulling the plug on a new receiver.
    – Ben
    Commented Jul 26, 2018 at 23:16
  • @Ben - would love to do that but not sure how... Any pointers? Commented Jul 27, 2018 at 10:49


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