peugeot 205 1.4 TU model 1999 - original immobilizer fault

[amitai12]

Hey.
I own a 1999 Peugeot 205 1.4 with an original immobilizer.
In recent weeks, the immobilizer has gone crazy and no longer requires a code to drive the vehicle and automatically there is a green light when the switch is turned on.
On the other hand, it cuts off the fuel/ignition in the engine during the drive or while standing and constantly turns off my car.
I noticed that from time to time when the car is on, both green and red lights appear together on the immobilizer many times at the same time as the car is turned off.
I tried to start with the code and then while the engine is running to disconnect the immobilizer connector, but it didn't work.
I tried to replace the current ECU with another suitable one that does not have an immobilizer chip, did not work too.
The engine keeps turning off.
I'm really lost.
is there a way to disable / bypass this system in my car?
If not, what are the ways to fix it?
Is there anywhere I can find a manual or diagrams for this system?
(I didn't find it in Haynes and I didn't find it in the owner's book)
I saw that there are buttons S, C on the immobilizer. Could it be possible to reset the system through them and everything will be fine?
Is there perhaps a battery somewhere that needs to be replaced and should be checked to see if it has run out?

I would be very grateful for help on this very urgent matter, thank you very much in advance!

[xantia_v6]

The symptoms that you describe seem to indicate a failure in one of the power feeds to the ECU rather than an immobiliser fault.

Simultaneous red and green lights means that the immobiliser is awake but cannot communicate with the ECU.

The immobiliser being already unlocked when the ignition is switched on usually means that the ECU lost its power supply before the immobiliser completed the locking sequence last time it was run.

The first thing to try is replacing or swapping the relays that feed power to the ECU.

[wheeler]

Agreed, This is unlikely to be anything to do with the immobiliser. Even if you fitted an ECU without immobiliser function i suspect it would not cure the problem.
Without going into in depth wiring checks the first suspect would be the 'double' injection relay, they are known to be troublesome, especially on older models.

[Huskyxantia]

[CitroJim]

That's a very late 205!

Also check the ECU earth connections... There will be several and all can cause this sort of issue...

Also, with the battery disconnected, disconnect the big plug on the ECU and reconnect it to ensure it's properly seated... Also repeat for the double injection relay... The act of disconnecting and reconnecting will also clean the surfaces of the pins to an extent...

A wiring diagram, harness diagram and component location diagram may help identify all the potentially suspect earths and the positive supply lines...

On submission of your VIN - don't worry, it'll be hidden from general view - the forum staff may be able to assist in providing such...

It may be helpful to state if your car has Bosch or Magnetti Marelli injection and whether single or multi-point...

I may be able to provide some generic diagrams knowing the above information...

[wheeler]

I assumed this was a petrol model as the OP has said TU engine & not TUD??

[MattBLancs]

I assumed this was a petrol model as the OP has said TU engine & not TUD??

Ha ha, read the above and had a train of thought as follows:

Hmmm, didn't think the 205 ever had the (1.4, 1.5) TUD engine fitted (only saxo, 106, Metro).... Hmmm, thought 205 ended production in 1996 (maybe 205 carried on elsewhere and so did get a TUD fitted??) ..... Began watching video, skipped ahead to engine bay waffling.... Thought hmmm, didn't think the TUD had a Bosch pump .... Then a bit later, oh wait, that's a 306. And so it's an XUD. As would be fitted to a 205.

In short ignore me jumping to the wrong conclusion, repeatedly, in the background!

Matt

[CitroJim]

A few PSA vehicles did live on for a surprisingly long time in some territories Matt... Wikipedia does say production ended in 1999... Similarly, the AX lived until 1998 in some parts of the world and then went on to survive into the 21st century as the Proton Tiara!

The 205 had the 1.7 XUD usually normally aspirated but a few did have the turbo version and they went like rockets and faster than the GTi! I once had a 205 STDT and it was fun... Shame was it proved beyond repair due to accident damage but for the short time I had it I loved it

Wikipedia makes no mention of the 205 ever having had a TUD but it did say some had the XUD9 but doesn't elaborate... I'm never aware of a factory XUD9 205 but I do know a few ended up with the 1.9TD after engine transplants... They must be super fun to drive!!!

[MattBLancs]

Wasn't aware the 205 lived on but did know the 405 was reincarnated, it seems to have never actually ended - continued built in Iran, then facelift to become a Peugeot Pars
https://en.wikipedia.org/wiki/Peugeot_Pars

Wikipedia reckons this is running on 405 underpinnings:

https://en.wikipedia.org/wiki/IKCO_Dena

Still available today! Should be no shortage of 405 rear suspension assemblies any time soon!



Whilst we are well off topic, the Dena's engine must be contender for longest auxiliary belt award!

Round and round and round it goes!

https://en.wikipedia.org/wiki/IKCO_EF_e ... Engine.jpg

[CitroJim]

Gosh!

[amitai12]

Hey.
Thanks for all the answers, I started looking for another double injection relay to replace and see if there will be an improvement.
xantia_v6, can you maybe guide me where to find the ECU relay?
Huskyxantia, I came across this video on YouTube during my searches, do you happen to know if what is shown in the video is also true for the gasoline engines?
In the meantime, these are the findings:
CitroJim, I have single point injection and my throttle body is bosch. I don't know about the injector itself, but I assume it's probably Bosch's as well.
I haven't checked the earth of the ECU yet. I would appreciate it if you could guide me where to check.
I took out and put back the ECU and the double injection relay and there was no change.

I played a lot over the weekend with the C, S buttons on the immobilizer. I tried all kinds of patterns and occasionally typed the code without knowing what I was really doing. But I heard several beeps and a few minutes later I returned to the car and the immobilizer reset, and since then it has returned to itself and there is a steady red light when the switch is ON, and the code must be entered to start.
Also only the green light turns on immediately after entering the code and the red light turn off and it starts. but the problem of the two lights being on repeats itself sometimes.
I will also mention that yesterday I found very, very subtle contact problems in the connection between the connector, and the electronic board of the immobilizer itself.
It turns the immobilizer board on and off again every time I play with them and also immediately after it turns on the 2 lights come on together.
As a preliminary test, I temporarily tried to fix the wires and the connector with a slightly taut insulating band, so that they would not move from the small vibrations of the engine. The car idled for half an hour the first time and only then turned off. I repeated the action, making sure the contact was as good as I could. But this time during idling the two lights suddenly appeared again and the engine turn off afterwards.
Maybe for a brief moment the contact loosened and caused it to turn off and on again without me knowing (because in a normal preventive mode in any case both lights should be off), and maybe the problem is not just the contact.
Could it be that a loose connection, even though I tried to fix it temporarily, will cause these disruptions and that's the whole story?
Could it be possible that as a result of turning the immobilizer off and on again, damage to other components should be checked after repairing the contacts?

I have attached some pictures.
thank you all.

[CitroJim]

Good, knowing it's a Bosch single-point means it's very similar to what's on my Citroen Saxo.

The double injection relay is common across many, many PSA vehicles of thee period...

I've running short of time right now but here's the generic wiring diagram for the Saxo, which I'm sure will be very similar to the 205...

I apologise for the quality as it's a mobile phone photo from a poorly printed book... Hopefully the forum staff can do a bit better when they have your VIN...

This should allow you to identify the earths and power supplies to the ECU (item 42) both direct and via the double relay (item 27).

Don't play too much with the immobiliser keypad at this time and don't discount the possibility the keypad itself may have a fault. You can try another keypad as the code is stored in the ECU.

Swap keypads only with the battery disconnected.

I hope this will help a little...

[amitai12]

VIN - VF3**************[VIN obfuscated, can be read by forum staff]

[amitai12]

Okay, these are the new findings:

I saw on this site: https://www.205gtidrivers.com/articles/ ... relay-r98/ an article on Tachymetric Relay.
It was also written there that it could cause problems of the kind I'm experiencing.
I'm not sure about its location but I checked a small black box with a fuse on top near the left headlight and radiator of the vehicle.
It looks full of rust and corrosion and all the plastic of the box is completely crumbling.
After I pulled out the battery to create easy access and pulled the box out of place I discovered a connector that had completely disintegrated and was disconnected, I'm not sure about its function and whether it was connected to the black box because it's 3 pins connector, and the available pins in the black box are 2 pins.
Attach photos.

[CitroJim]

That's the main engine fusebox and could well account for all your issues...

I will try to dig you out some more applicable wiring diagrams... I do have some 205 stuff but fear it may be too old...

Do be aware the 205GTi is a very, very different car from yours... And yours will not have a tachymetric relay... Those were only used with the Bosch LU2 Jetronic system on the XU5 and XU9 engines...