Possible immobiliser issue?

[Sommevr6 10]

Hi everyone, after a bit of advice in relation to an ongoing issue I'm having with my Corrado. When I go to start the car it sometimes fires up first time but on other occasions will start and die immediately. When it does the latter it can then take any number of attempts before it eventually fires up. It will then drive normally but becomes a potential lottery if you then stop and restart. The car has been standing for a while and I've had to charge the battery on occasions. I suspect, from reading various threads on here and other sites that it might be immobiliser related. The car appears to have a Toad alarm fitted but I don't know which model as it was already on when I got it and there is no paperwork in the cars history file relating to it.

If it is the immobiliser, is it a factory immobiliser or will it be an immobiliser related to the Toad system?

[seanl82 23]

It'll be the factory immobiliser if it starts then cuts out. Aftermarket will either not crank at all or crank but not start. When attempting to start after the initial try, does it start then cut out again, or just continue to crank with no starting at all? Could be a few different things tbh, many of them quite common.

[Dox 23]

The easiest thing to do is try a spare key.

 

Make sure there's only one car key near the ignition barrel as the immobiliser can read the wrong key if they are on the same ring.

 

Ignition switches are a common failure too

[swiftkid 1]

Definitely the factory immobiliser, my toad won't even let me crank if its armed. I have had similar issues in the past, people have said about just unplugged then plugging the wires back in into the transponder and earth, worked for me once or twice. The transponder is tucked up behind the dash near the fusebox, you need to be triple jointed to reach it though. I'd maybe say the underlying issue is the halo though

[Sommevr6 10]

Thanks everyone for the responses. I've had an auto electrician out and Sod's law it started first time for him. He did stop and start it several times after, during which the problem re-emerged. We tried the spare key and it started ok with that but on doing a quick diagnostic via the obd port it was showing only one fault, relating to the crank position sensor. He tried TPS re availability but it seems to be another discontinued part. Does this sound feasible as the cause of the issue or is it going to be a process of elimination job?

[Dox 23]

Thanks everyone for the responses. I've had an auto electrician out and Sod's law it started first time for him. He did stop and start it several times after, during which the problem re-emerged. We tried the spare key and it started ok with that but on doing a quick diagnostic via the obd port it was showing only one fault, relating to the crank position sensor. He tried TPS re availability but it seems to be another discontinued part. Does this sound feasible as the cause of the issue or is it going to be a process of elimination job?

 

You will get a crank position sensor code if you scan the car with the engine not running even if its perfect. A faulty crank sensor will give the symptoms of no spark or fuel injected

[fla 9]

I have a spare halo and immob unit if you need it

[Sommevr6 10]

Thanks for that Dox/Hasan. Forgive the ignorance but with the spare halo and immobiliser unit would the halo device replace the existing one on the ignition or would it require a new barrel aswell. Would this also require the keys to be re-programmed to the new halo if a new barrel and presumably new keys weren't required. As you can probably tell mechanics/electrics are not my strong point!!

[swiftkid 1]

The halo is just a reader so you can swap that over but the transponder is chip specific, you can swap the chip over but I doubt the transponder is faulty. The halo just unclips or unscrews from the column, fairly straight forward swap.

[Tjninny 10]

I had the same problem, and while I don’t use the car every day, it’s been fine since I made sure the connection at the end of the halo cable was clean (advice from this forum)Worth starting with this easy fix.

[fla 9]

Thanks for that Dox/Hasan. Forgive the ignorance but with the spare halo and immobiliser unit would the halo device replace the existing one on the ignition or would it require a new barrel aswell. Would this also require the keys to be re-programmed to the new halo if a new barrel and presumably new keys weren't required. As you can probably tell mechanics/electrics are not my strong point!!

 

I've got the transponder from the key taped to the halo! But you could just remove it from your key and use it again. But its worth cleaning the connector first to.see if it solves.the problem.