Re. Car won't start and Immobiliser key indicator lamp on

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Xsara2003
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Re. Car won't start and Immobiliser key indicator lamp on

Post by Xsara2003 »

Hi,

I have a 2003 Citroën Xsara 1.4i that I bought second hand back in 2008 with 115,000km on the clock. A few weeks after purchasing the car the Engine auto-diagnosis light came on and the car would get very sluggish and stalls at times. After a few visits to the Citroën "specialist" and with a lighter wallet, the problem wasn't entire solved: it was better but it basically lacked power and while driving sometimes you could feel like the car was just cruising for some split seconds. I got a job overseas and didn't use the car for two years - my friend was using it occasionally. When I came back in 2010, I had to change the fuel pump. I also changed the clutch and timing pulley belt and pulley. From then on and for the next 6 years, the car drove fine. The Engine auto-diagnosis light was still on but I could climb some hills on 5th gear and I was getting fuel economy of up to 20km per litre! Occasionally, the rear wiper would come on and on other occasion my low beam would blink!

Lately, I could get my high beam to stay on.

Two weeks ago, I left home early in the morning and it was raining. The car started fine. I had to stop to changed a flat tyre... but then the car would not crank and after a few tries the Immobiliser light came on. Later on I tried to jump start the car but still it would crank. I charged the battery and now it would crank but won't start.

I don't have the spare key and the coded card. What could be the issue?

Thanks in advance.

Julien

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GiveMeABreak
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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by GiveMeABreak »

Hi and welcome to the Forum.

First thoughts are that as you have changed the battery, you may need to pair the transponder with the immobiliser again, otherwise this is what can happen - the car will turn over but won't start. That is part of the immobiliser doing its job. I can't remember the procedure for the Xsara, but it is probably similar to other PSA cars. Leave the car for a while after you have tried starting it. After about 10 minutes, put the key in the ignition but do not try to start the car yet. Hold the lock button down on the remote control for 5-10 seconds, release the button, take the key out of the ignition. Now close the doors and try and lock the central locking with the remote fob. Open the car and then try and start the vehicle as normal.

Xsara2003
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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by Xsara2003 »

Dear Marc,

Thanks for your reply. I forgot to mention that for quite some time now, the fob doesn't work (probably low battery) and I was referring to the car battery and not the fob battery. I have already tried the above but still wouldn't start: I will change the fob battery and try again.

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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by GiveMeABreak »

Yes that's what I meant, this happens when the car battery is disconnected. The fob needs to be paired back with the immobiliser. Make sure the cob has a good battery too.

Xsara2003
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Joined: 28 Apr 2017, 17:10

Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by Xsara2003 »

Changed the battery in key fob and reinitialised it but car still won't start. I've heard that in some cars the immobiliser stops both the fuel pump and the starter from activating but in my case fuel is coming and the engine cranks. But the spark plugs don't fire. Will a mechanical and/or electrical problem with the engine activate the immobiliser?

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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by GiveMeABreak »

Post up or PM your VIN so I can see what you have. It may help.

Xsara2003
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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by Xsara2003 »

VF7**************[VIN obfuscated, can be read by forum staff]

Also I believe that the BSM has been changed (by the Citroen specialist I went to see some time back) as the fuses positions don't match the table of fuse in the owner's handbook

Xsara2003
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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by Xsara2003 »

Actual BSM
Attachments
BSM.jpg

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GiveMeABreak
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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by GiveMeABreak »

Ok, so your car has the ADC2 immobiliser, which on your petrol car locks the engine ECU as opposed to the Diesel ADC1 system that locks the diesel pump solenoid valve.

Check the following fuses: Engine Compartment 10Amp fuse F5, which is for the Engine ECU, the Auto Box (if fitted) and the Alarm Siren:
Xsara Engine Fuse F5
Xsara Engine Fuse F5
Also there is a 10Amp fuse F7 in the passenger compartment that deals with the alarm unit amongst other things, so may be worth checking.

Key:
BSI - Built In Systems Interface
CV00 - Switch Module at Steering Wheel
8209 - Transponder Coil
0004 - Instrument Panel
8606 - System Status LED
1320 - Engine ECU
A - Transponder Key
(Single Arrow = wire connection, Triple Arrow = Multiplexed connection)

Connections:
  • 3 - Request for lighting of the key transponder fault warning lamp - Comfort VAN
  • 4 - Request for key transponder identification. Request for key transponder authentication - Body VAN 1
  • 5 - Request for key transponder identification. Request for key transponder authentication - Analogue
  • 6 - Request for key transponder identification. Request for key transponder authentication - High frequency link
  • 7 - Transmission of the key transponder identifier. Transmission of result of the authentication calculation - High frequency link
  • 8 - Transmission of the key transponder identifier. Transmission of result of the authentication calculation - Analogue
  • 9 - Transmission of the key transponder identifier. Transmission of result of the authentication calculation - Body VAN 1
  • 10 - Ignition on information. Information authentication of the connection - CAN
  • 11 - Random number sent - CAN
  • 12 - "System state" led control - Analogue
ADC2 Xsara Immobiliser
ADC2 Xsara Immobiliser

Xsara2003
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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by Xsara2003 »

The plan is the same as that in the owner's handbook but it doesn't correspond to the one on the car. I believe the BSI has been changed in the past. For what it's worth the one is a Delphi with the following written on it 9646405280 BSM B3. In any case I have checked all the fuses on it and they seem to be ok. I will check again and check the F7 in the passenger compartment.

If the ADC2 Immobiliser locks the Engine ECU, does it mean that a defective ECU or any components linked to it will not trigger the Immobiliser but the car won't start and fault will be reported?

If the above is true, then the problem would be with one of the following: transponder key, transponder coil, bsi and everything that connects everything together. Will an engine diagnostic help?

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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by GiveMeABreak »

Yes if you have access to a Lexia that will help to identify ant faults.

Xsara2003
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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by Xsara2003 »

But can a faulty engine sensor activate the immobiliser?

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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by GiveMeABreak »

No, either the immobiliser ECU is faulty or there's a communication issue somewhere, so a diagnostic may give some pointers, otherwise you could end up replacing parts you don't need. Always best to go down this route once you have checked all the obvious things and ruled out any recent work that might have dislodged or caused the problem.

Xsara2003
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Re: Re. Car won't start and Immobiliser key indicator lamp on

Post by Xsara2003 »

We are talking the same language then.