Engine immobilizer fault!!

Talk about the 406's electrical system, what wires do what, how to add extra functionality, etc.

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sturose
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Engine immobilizer fault!!

Post by sturose »

Need help quite urgently guys, I'm in the middle of a house move and it's drawn to a halt because I can't get to the new house.

Car is Peugeot 406 hdi estate 52 plate.

Yesterday, stopped outside my current home, stayed 5 minutes, got back in the car and it was dead. No dash lights, nothing at all.

Popped the bonnet and checked the battery connections, earth was loose so I tightened it up. Jumped back in the drivers seat and tried to start but just continuously turned over. Dash had an orange light, square box with a key going through it. Turned the ignition on again and the panel said engine immobilizer fault.

I've read various potential fixes but none of the simple ones work. Quick rundown of where I'm at:

Car won't start due to immobilizer fault, key does not appear to be recognised as there is no longer a key reminder beep when I leave the key in the ignition with the drivers door open.

Spare key (original pug key) same thing so I guess a key fault is ruled out.

Tried bsi reset I found online, did nothing at all.

That's it, I have nothing else!! I've read about the immobilizer antenna going bad on these, could this be the issue?

I have no access to any diagnostic equipment so can't even test anything. Can't move the car so can't get it to a garage without recovery. It's not even my car, it's my moms and I really could do with getting it running again if possible. Obviously without spending hundreds as the car is just not worth that much now.

Any help will be greatly appreciated.

Edit: forgot to mention, missus was in the car at the time and she said she heard a fizzing/crackling noise when I reconnected the battery. Now I did get the usual sparking when I touched the terminal with the lead but she swears it sounded much closer like inside the car.
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steve_earwig
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Re: Engine immobilizer fault!!

Post by steve_earwig »

I guess the battery disconnect/reconnect is covered by the BSI reset. Hmm, crackling in the car, could be wet/corroded footwell connectors (under the driver's side carpet).
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sturose
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Re: Engine immobilizer fault!!

Post by sturose »

Thanks, I'll check that out. Hopefully it's as simple as that then. Just hope it's easily accessible.
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Re: Engine immobilizer fault!!

Post by steve_earwig »

sturose wrote: Thu Mar 04, 2021 12:33 pmsimple
Hmm, wait until you see it, how much of a job it'll be depends how bad it is. If it is that of course.
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sturose
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Re: Engine immobilizer fault!!

Post by sturose »

steve_earwig wrote: Thu Mar 04, 2021 1:51 pm
sturose wrote: Thu Mar 04, 2021 12:33 pmsimple
Hmm, wait until you see it, how much of a job it'll be depends how bad it is. If it is that of course.
:?

The carpet is a total nightmare to remove but nothing feels damp at all. Are there any fuses that are linked to this? I have no idea where anything is on this car!

Everything else in the car seems to be working fine. All I'm getting now is the engine immobilizer fault display and the symbol on the dash.
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Re: Engine immobilizer fault!!

Post by steve_earwig »

Şorry I made you lift the carpet, it could have been nasty (think connectors falling apart and wires corroded so far back there are no numbers on them) and seems quite common. Hmm, now I'm clutching at straws :(

52 plate I believe makes it a 2002, so it could be "semi-mux" or "full-mux", the change is from rpo 9001 about the middle of the year (they're actually all mux, just the later cars have a lot more of it and more integrated systems). There's nothing for the immobiliser on the full-mux fuse diagram ('cos it's now in the BSI) but on the semi I'm seeing mf12 & mf13 in the underbonnet fuse panel labelled as "anti theft contact power supply". I believe the MFs (yeah, me too) are maxi fuses, unfortunately I don't have a diagram that shows where they hang out :(

Other than that what's the state of charge on the battery? The systems can be a bit picky about this.
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Re: Engine immobilizer fault!!

Post by GingerMagic »

Hmmm indeed.

To follow the path - the chip in the key is read by the transponder ring, this in turn is connected to the Comms unit, which then goes to the BSI ( I think ) which then tells the engine ECU that all is well and you can fire up the car...

So, we've established it's not the key, so next to me line is the transponder ring, then the Comms unit.

You need to remove the lower part of the cowling to remove or check the transponder ring, so may as well check all the connections on the back of Comms unit ( grey connector is the immobiliser path )

Good luck, I was originally with Steve and thinking you have wet carpet syndrome, but if it's dry right underneath then it must be elsewhere...
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1998 Volvo 940 auto estate - also mine
2019 Citroen C3 something - the wife's
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Re: Engine immobilizer fault!!

Post by sturose »

Ok my mom realised she was still a member of the rac. We called them out and they can't figure it out. He said the key isn't recognised but as I have 2 keys it's unlikely to be the key itself.

I'm at a loss now. Is there anything else worth trying or do I have a very large paperweight?? I'm guessing there's no way to bypass the immobilizer on these things.
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Re: Engine immobilizer fault!!

Post by sturose »

It's an 02 not 52, my mistake. The rac guy checked several things. His plug in reader thing only came up with the key not recognised. He tried various things and put a variety of testers on the car but couldn't come up with anything. He did leave me a card for an auto locksmith but rather than pay for them to just check it over I'd rather ask here. I'm tight like that!! :lol:
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Re: Engine immobilizer fault!!

Post by steve_earwig »

sturose wrote: Thu Mar 04, 2021 7:12 pm It's an orange not a tangerine, my mistake.
:P :P I don't live in the UK 8) Looks like up until March 2002 they were on a 51 plate, 02 from March to September and 52 from September 2002 onwards. I'm pretty sure your ma's car is semi-mux then. The receiver rings do break yes, it's not common but we're heading that way. Oh, if you do see a com2000 unit then it's a full-mux :supafrisk:
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Re: Engine immobilizer fault!!

Post by GingerMagic »

Nothing wrong with being a little thrifty.... 8)

Whereabouts are you based?
2003 2.2hdi estate - mine
1998 Volvo 940 auto estate - also mine
2019 Citroen C3 something - the wife's
PP2000 user, can help with faults / diagnostics in the Bournemouth area.
sturose
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Re: Engine immobilizer fault!!

Post by sturose »

GingerMagic wrote: Thu Mar 04, 2021 8:10 pm Nothing wrong with being a little thrifty.... 8)

Whereabouts are you based?
I'm not thrifty, I'm tight as a ducks arse according to my missus :lol:

I'm based in Staffordshire.
steve_earwig wrote: Thu Mar 04, 2021 8:03 pm
sturose wrote: Thu Mar 04, 2021 7:12 pm It's an orange not a tangerine, my mistake.
:P :P I don't live in the UK 8) Looks like up until March 2002 they were on a 51 plate, 02 from March to September and 52 from September 2002 onwards. I'm pretty sure your ma's car is semi-mux then. The receiver rings do break yes, it's not common but we're heading that way. Oh, if you do see a com2000 unit then it's a full-mux :supafrisk:
Where would I find a com2000 if it has one?

You are correct re: the registration, in terms of fixing the problem is there much difference between semi-mux and full-mux then?
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Re: Engine immobilizer fault!!

Post by steve_earwig »

It's rather obvious viewtopic.php?f=10&t=17391 You should be able to tell just looking at the stalks with this :wink: There is a lot of difference in the wiring, fuse layouts, wiring, modules... I *think* the semi still has a separate module for the immobiliser (like the D8) , I don't have access to wiring diagrams any more as they went with my Windows 7 (the program is massive, tricky to install, once I was on it all the time but I didn't seem to be needing it any more) and PSA themselves stabbed us in the back by making Service Box (parts diagrams etc.) pay only. There are wiring diagrams for a full-mux (petrila) but I don't think there's anything for a semi.
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sturose
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Re: Engine immobilizer fault!!

Post by sturose »

Ok thanks for the help guys. After the rac being unable to find a way to get it started I'm not sure I would be able to fix it.

I'm in the middle of a house move at the moment and just don't have the time. I hoped for a quick fix but that's clearly not going to be the case. It's a shame really because it's an extremely smooth running vehicle but no use to me if it doesn't start.

Not sure if it's going to just be scrapped now, that'll be up to my mom.
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Re: Engine immobilizer fault!!

Post by steve_earwig »

I've been off a searching: Wet carpets, disconnecting the battery without letting the BSI go to sleep (I know you've not done this), wiring issues, the BSI has lost communication with the engine ecu, you need to take it to Pug, your key needs reprogramming and.... I pulled off the receiver around the key barrel, looked at it and put it back, the car's been fine ever since.

I get that if the issue is serious it'll write the car off, it's a shame but as their value approaches that of scrap metal it makes sense.
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