Xantia 2 1.9TD ECU / Immobilizer issue

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Xantia 2 1.9TD ECU / Immobilizer issue

Post by Deacon » 15 May 2018, 15:30

Hello,

My young lady just got new belts, pulleys, and tensioners for her 200 000 km anniversary. To do the job, the service guy disconnected the ECU (for 3 days until everything got put together). The Immobilizer has been removed sometime in the past and the solenoid on the pump (that allowed fuel after a signal from the immobilizer) is now activated via a wire from the ones that were previously connected to the now removed immobilizer.

Right, so now after everything was put together, the car didn't want to start (nothing was touched in the wiring). On ignition, the wires, connected to the solenoid didn't pass current. So, a 12V wire from the battery to the solenoid opened it and the car started, BUT the smart injector (it's a '98 XUD9TE, with the DHX VIN code) isn't activated, there's no power to the ECU (and the relays in its box), the advance of low/high RPMs on the fuel pump isn't working, and the glow plug light isn't showing (thought, glow plugs are working).

The car runs now, but with bypassed ECU, it runs like a dog, smokes and without the "smart" function of the smart injector, I can count the number of times it is opening and closing.

The questions that I have are: Is it possible that when the immobilizer was removed, they did something in the ECU and we did reset it now after being disconnected for so long from the car? What exactly the ECU does control on the last/latest XUD9TE engines with Bosch fuel pump?

The car is scheduled for an appointment with an electrician these days, but any bits of advice would be welcomed!
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Xantia Estate MK.2 1.9 TD, 1999

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Re: Xantia 2 1.9TD ECU / Immobilizer issue

Post by MikeT » 15 May 2018, 16:27

The ECU controls ignition timing, fast idle and EGR.
If it was working before, have you checked the fuses and connectors?
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98 S2 Xantia Hatch 1.9TD 143K
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Re: Xantia 2 1.9TD ECU / Immobilizer issue

Post by Deacon » 15 May 2018, 16:38

Hi Mike,

Thanks for the prompt reply!

So, it appears that the ECU isn't getting any power and from there on the ignition timing control and fast idle aren't working. But hey, the fuel pump is working :D (good old mechanical injection). I haven't checked the fuses myself, but I was told they are OK. Hence, they might not be. I will check them the day after tomorrow myself. As to why there is no power to the relays in the ECU box (not the ECU itself, this isn't tested), I have no idea. The service guy said that he only did: change battery connectors (old ones were the original and were looking sorry) and he sprayed the electrical "distributor" plate just to the right of the battery with anti-corrosion spray. The same goes for the ECU connector, he says there was oxidation and he cleaned it with that spray.

Also, the technician said the ignition contact might not be working correctly, though that is highly unlikely in my opinion. The car was running great when I left it a few days ago. Must be something he disconnected.
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Re: Xantia 2 1.9TD ECU / Immobilizer issue

Post by MikeT » 15 May 2018, 16:54

I'm puzzled why the mechanic disturbed the ECU at all.
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Re: Xantia 2 1.9TD ECU / Immobilizer issue

Post by MikeT » 15 May 2018, 17:39

Can you confirm these are still plugged in? (see first post, second photo) viewtopic.php?t=49686
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98 S2 Xantia Hatch 1.9TD 143K
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Re: Xantia 2 1.9TD ECU / Immobilizer issue

Post by Deacon » 15 May 2018, 17:49

Yep, these things look sort of unrelated, but I guess they are caused by the same problem. The way I see it is: The ECU thinks that the engine should be off, but we start it nevertheless with 12V to the fuel pump solenoid+normal contact, therefore bypassing the ECU check for immobilizer, which leads to rough engine operation.
I checked the pictures. Both connectors should be plugged in, right? I will check tomorrow and I will report back.
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Re: Xantia 2 1.9TD ECU / Immobilizer issue

Post by Deacon » 20 May 2018, 18:04

I was busy these days, today I checked that plug and it is in place. I got no more ideas. Waiting for the visit with the auto. electrician.
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Xantia Estate MK.2 1.9 TD, 1999

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Re: Xantia 2 1.9TD ECU / Immobilizer issue

Post by kenbw2 » 21 May 2018, 16:05

I didn't realise the XUD9 ever had an ECU. When did they come in?

I assumed the XUD9 was phased out roughly the same time they put ECUs into the DW8/TUD5 engines.
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Re: Xantia 2 1.9TD ECU / Immobilizer issue

Post by Deacon » 22 May 2018, 14:30

kenbw2 wrote:
21 May 2018, 16:05
I didn't realise the XUD9 ever had an ECU. When did they come in?

I assumed the XUD9 was phased out roughly the same time they put ECUs into the DW8/TUD5 engines.


It appears that the last 1.9TD models were running the latest ever attempt to tame the XUD9 in terms of electronics, noise, economy and polution. Mine has the XUD9TE version of the engine. My electrician knows these cars like the fingers on his hands and says there were 4 or 5 in total, versions of the XUD9 with different injection / fuel pump system models. When all the electronics are working, mine works quite smooth and silent (when warm) and the diesel "knock" isn't that audible. For example. at 2000 RPM you will still hear the diesel-like motion and noise of an HDI, while in the XUD it seems like a petrol car (no diesel noise, it just hums). Also, the car moves quite well for its 1500 kilos and just 90HP.

My neighbor still rocks a good old 405, rocking a non-turbo early XUD9. Man that thing KNOCKS when cold. Just like mine, without the ECU controlling the pump... And now the dynamic of my engine is gone as well. :(

Fingers crossed. Somewhere around the 1st of June, I am bringing her in with the technician.
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Xantia Estate MK.2 1.9 TD, 1999