Technical immobiliser problem

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Technical immobiliser problem

Joined
Feb 28, 2021
Messages
35
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Location
Forest of Dean
OK, just joined the forum as I have a problem with a 2004 MkII 16v Punto Active Sport. The immobiliser light (car/padlock symbol) is on when you turn the key in the ignition. Cranks as it should but obviously will not fire. New battery recently fitted as the car has stood for 3 months and old one would not hold charge. Both original keys have been tried - no joy. Main earthing point has been cleaned. Before it had this lay-off a new exhaust was fitted (failed MOT) and when being road tested the car cut out but would re-start on the key. When left idling it would also cut out. Blip key activates central locking and the alarm beeps as it always has done.
Any ideas? Can't get it to a garage as no MOT and, obviously, it won't start!
I've looked at other threads and tried the simple things suggested but no joy. Taken the air filter housing off but can't see the small earth lead referenced in one post - different model? Currently has +ve connection on battery with -ve unconnected as I've also seen this as something to try.
Thanks in advance
 
You would be sensible to focus on the imobiliser not turning off before anything else.

Getting MES and a lead to connect to to the ecu will help you find out why the imobiliser is not turning off.

The is an ariel ring around the ignition barrel that detects the coded chip in the key. Has any work been done near ignition barrel?

Long shot but try connecting a jump lead from battery -ve terminal and clean metal point on body work , not engine, see if any difference.
 
Many thanks judderbar. I'll have a look at this in the morning. Thanks again for taking the time to offer advice, much appreciated!
 
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Thanks for this Jackwhoo. No work has been carried out on the ignition or steering column. I'll have a go with the jump lead long shot in the morning. Please excuse my ignorance as a newbie but MES?
Thanks again
 
Thanks for this Jackwhoo. No work has been carried out on the ignition or steering column. I'll have a go with the jump lead long shot in the morning. Please excuse my ignorance as a newbie but MES?
Thanks again
Mes=Multi ecu scan
Software that allows laptop to talk to your cars ecus via a cable that connects usb port to the obd2 diagnostic port in your car.
 
Mes=Multi ecu scan
Software that allows laptop to talk to your cars ecus via a cable that connects usb port to the obd2 diagnostic port in your car.

Tried the long shot and no joy. Also double checked the ECU earthing point - removed, cleaned and replaced. Still no joy. I'm now going to try to find a local mobile car electrician to plug in the gizzmo to see what that says!
Thanks again
 
Morning. Checked the earth and all good. Took off, cleaned and replaced. Time to find someone with a diagnostic computer! Thanks again for taking the time to reply to my question, most appreciated.
 
Many thanks judderbar. I'll have a look at this in the morning. Thanks again for taking the time to offer advice, much appreciated!

morning. Checked the earth and all good. Took off, cleaned and replaced. Time to find someone with a diagnostic computer! Thanks again for taking the time to reply to my question, most appreciated.
 
morning. Checked the earth and all good. Took off, cleaned and replaced. Time to find someone with a diagnostic computer! Thanks again for taking the time to reply to my question, most appreciated.
When you get it fixed please let us know what problem was.
 
morning. Checked the earth and all good. Took off, cleaned and replaced. Time to find someone with a diagnostic computer! Thanks again for taking the time to reply to my question, most appreciated.

Hi

As its had a garage driving it..

Undo the steering rake adjuster..

Move it through a few Arcs.. then clamp and try key again

IF they have moved it.. its possible it has interrupted the signal from 'key aeriel' to ECU

Where are you based?
 
Interrogating the ECU to see what it has lost..

Ithat is your best course of action.. :)

Thanks. Trying to get a mobile mechanic with suitable diagnostic kit. That or having to trailer/tow the car to a garage!!! I'll post an update once I have one.
Thanks for you help - much appreciated.
 
Jackwhoo & Varesecrazy, had a sparks look at it with a computer. Keys, aeriel and immobiliser are all talking to each other but not, it appears, to the ECU! Tried a 'virgin' plug and play replacement ECU but no joy. Now noticed something strange with the wiring loom on the ECU plug closest to the radiator. It looks as though a couple of wires have been chewed but on closer inspection its the protective ribbed cover that has rubbed through at least 3 and one of the cables - pink - has taken out a few of the strands. I'm going to splice in a repair to see what happens. The large black earth has also been rubbing somewhere and the plastic sheath worn through to expose the wire in 2 places.
Also noticed - strange how we often look without seeing - that the oil light does not come on when the ignition is on.....everything else appears to be! Have to investigate the oil sensor and wiring plus related fuses (again).
Hey ho....tomorrow is another day (Hopefully as Capt Sir Tom said - a Good day)
I'll post a photo of the wiring once I've downloaded it from my phone.
 
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