Immobiliser fault?

BoozerDawg

BoozerDawg

BoozerDawg

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Driving to work the other day, half way there the car cuts out, dashboard lights up fully so I pull over. I give it a few minutes, then it starts up again and off I go. Couple more miles down the road it cuts out again exact same way, but this time it wont start up again (no cranking or anything). AA come out to have a look, and find the alternator has burnt out (copper wires all grey and could smell electrical burning). AA guy disconnected the alternator and charged the battery from his van, hoping it would give me enough charge to get me to a nearby garage.

Doesn't get me very far, car cuts out again, however I noticed that the dashboard was lit up and pushing the accelerator did nothing, the engine was still running (it may have been running the last 2 times but in the "ffs" moment I didn't notice). Anyway, the AA guy hooks up a portable battery and this time I reach the garage.

An alternator, new belt and battery later, told car is ready to pick up, do so, car started up just fine, and while I'm sat in the car park texting, the exact same thing happens again, and wouldnt start again (no cranking, nothing).

Garage take another look, and found a fault code relating to the immobiliser , and suspect that either my key's messed up and the signal is breaking down, or the immobiliser has gotten damaged by the failing alternator (old one was apparently kicking out 19v when it should have been 15v).

Today i'm going to try the spare key I have, but I just wanted to check if this all sounds about right? Garage said if its not the key then I could be looking at a who knows what electrical components got damaged situation and it might be worth scraping. Which I understand, but paying £450 1 day and scraping the next is a bit of a gut punch (ideally Id try and get the car home to rip out the new parts and sell them to recoup some costs first).

What say you?
 
What's the car? Make/model..

I doubt this is going to be the key, most cars only use the immobiliser system/checking software codes when unlocking and starting, once running it's left alone. Though I guess the fact you get nothing sometimes after it dies could point to that, but if the immobiliser signal is lost whilst driving it shouldn't cause the car to die. It could be the actual ignition switch though.

This sounds to me like a power issue, a voltage spike or drop etc causing the car to shut down for safety reasons. CEM could be at fault?

When you say the car doesn't start at all, do you still get power in ignition pos II? If you move to pos 3 do you hear the relay to the starter motor click?
 
Ford Focus 1.6 diesel (2007). After it conks out and I try to restart it, there's nothing, no sound or clicks anywhere. Give it a few minutes and it may start up again. Garage said they had it conk out, but managed to get it going again by turning the key around and trying again.

My memory on what happens at pos II is flakey, but I think nothing at all came on electronically. Will update when I go back later today to try and get it out of the garage.
 
Sounds like ignition switch needs replacing to me. You should be able to buzz it out with a multimeter if you can get it out the car to confirm.
 
So an update, I went to collect the car again with the spare key, but the mechanic said he'd been looking more into it and no longer thought it was the immobiliser, ash he had found many people with the same problems online suggesting the instrument cluster was at fault (contacts breaking etc). So I left the car there until today when the roads are quiet. Car wouldn't start ..... so I punched the instrument cluster, and it fired up.

Made it half way and it cut out again, quick punch and everything came back on again. Had a few more cut outs on the way, and few more punches got it going again. So I'm pretty certain now the instrument cluster is faulty!

To note, on pos II, all electronics were working (blowers/stereo/lights etc), but the instrument cluster just lit up fully and showed "---" for mileage, but would not even attempt the starter motor. After punching it once it was back to normal (for most of the journey anyway).

Anyway, punching a car to get back home made me laugh.
 
BoozerDawg said:
So an update, I went to collect the car again with the spare key, but the mechanic said he'd been looking more into it and no longer thought it was the immobiliser, ash he had found many people with the same problems online suggesting the instrument cluster was at fault (contacts breaking etc). So I left the car there until today when the roads are quiet. Car wouldn't start ..... so I punched the instrument cluster, and it fired up.

Made it half way and it cut out again, quick punch and everything came back on again. Had a few more cut outs on the way, and few more punches got it going again. So I'm pretty certain now the instrument cluster is faulty!

To note, on pos II, all electronics were working (blowers/stereo/lights etc), but the instrument cluster just lit up fully and showed "---" for mileage, but would not even attempt the starter motor. After punching it once it was back to normal (for most of the journey anyway).

Anyway, punching a car to get back home made me laugh.
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Came in here to suggest the instrument cluster. Seems odd but it is a common fault, will also show random seemingly unrelated error codes as well
 
100% it's your instrument cluster. Very common fault on the mk2 Focus.

You can fit a second hand unit from ebay for £50-100 and with an appropriate Ford-specific CANbus adaptor from eBay and a copy of Forscan you can then program your transponders to it. You'll need to register to get the advanced version of Forscan to do the key coding though.
 
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