Citroen XM - lost contact with ECU

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Re: Citroen XM - lost contact with ECU

Post by xantia_v6 »

I think that Chris may have been looking at a diagram with some incorrect pin numbering.

I am using the Citroen diagram 518-05/62 as my reference. If you give your RP number and confirm your transmission type, I can find the exactly correct diagram.

On the double relay, the primary relay coil is connected between pins 2 and 10. With the ignition switched on, there should be 12V on pin 2 and 0V on pin 10, resulting in 12V appearing on pin 1 and pin 9. If those voltages are OK, then the primary half of the relay is operating normally.

The secondary relay coil is connected between pins 14 and 7. There should be 12V on pin 14, and (controlled by the ECU) either 0V or 12V on pin 7. If there is 0V on pin 7, the relay should be energised, and 12V should appear on pins 4, 5 and 13, energising the rest of the ECU.

Can you check those voltages and let us know what you find before we move on to more tests?
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Re: Citroen XM - lost contact with ECU

Post by white exec »

Mike,
So far as I can see, you list the same pin configuration as Gabor's diagram.

It would be good, as you say, for us to have the exact RP number (or VIN number) of the car, so we are looking at exactly the correct diagram.
Chris
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Re: Citroen XM - lost contact with ECU

Post by xantia_v6 »

Chris,
white exec wrote: 26 Nov 2019, 18:49 Mike,
So far as I can see, you list the same pin configuration as Gabor's diagram.
Your earlier instructions implied that pin 10 is controlled by the ECU, but it is connected permanently to earth
white exec wrote: 15 Nov 2019, 17:09 Now to the second relay in the Bitron double...
With IGN ON:
- Briefly Gnd pin 10 on the Bitron connector, and you should hear this second relay click on. Check that pin 40 on the disconnected Inj ECU connector does the same thing.
- Check that it brings +12 to pin 9 on the Bitron connector, and to pin 20 on the Inj ECU connector.
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Re: Citroen XM - lost contact with ECU

Post by white exec »

OK, pin 10 is perm Gnd in 518-05/62, but Gnd via the ECU's pin40 on Gabor's circuit.
The suggestion to Gnd pin 10 was simply to test the relay action..

This is why we need VIN or RP number now.
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Re: Citroen XM - lost contact with ECU

Post by Mateusz »

white exec wrote: 26 Nov 2019, 16:42 +12v on pin 2
– on pin 10
when the relay is powered, you should get continuity between pin 1 and pin 9, and pin 11 and pin 9, and pin 1 and pin 11.
2-10 NO powered : 1-9 / 11-9 / 1-11
2-10 powered : 1-9 / 11-9 / 1-11
Checked on two bitrons, same result
xantia_v6 wrote: 26 Nov 2019, 18:13 On the double relay, the primary relay coil is connected between pins 2 and 10. With the ignition switched on, there should be 12V on pin 2 and 0V on pin 10, resulting in 12V appearing on pin 1 and pin 9. If those voltages are OK, then the primary half of the relay is operating normally.
ALL ok, also powered pin 20 in ECU inj.
xantia_v6 wrote: 26 Nov 2019, 18:13 The secondary relay coil is connected between pins 14 and 7. There should be 12V on pin 14, and (controlled by the ECU) either 0V or 12V on pin 7. If there is 0V on pin 7, the relay should be energised, and 12V should appear on pins 4, 5 and 13, energising the rest of the ECU.
Ingognition OFF - pin 14 powered
Ingognition OFF - punctured wire 7 to check power but then relay click
Turning Ingognition ON - something clicking inside relay
Pins 4,5,13 i checking with unpluged ECU connector.
I grounded 45 pin in ECU to make relay click then checked pins: 47-powered, 48-powered, 49-NO powered.
Looking pins 49<->13 and there is continuity so don't know why 49 is not powered. Also replaced to another bitron and same result
white exec wrote: 26 Nov 2019, 19:14This is why we need VIN or RP number now.
Spoiler: show
Automatic gearbox 4HP18 (20GZ1A)
VIŃ : VF7**************[VIN obfuscated, can be read by forum staff]
.
.
.
Going next i dont have power on 14 pin in Anti thief kbd and no continuity between Diag box C1 and C2 with inj Ecu. In circut diagram all of these going throught "Black square number 10" what was this?
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Re: Citroen XM - lost contact with ECU

Post by white exec »

Bit of progress.
Thanks for the VIN number. This shows that the car's RP (production date) number is 7522 (= 13 June 1997). This number should be painted on a front A-post, between the front door hinges. Might say CJ7522, or something like.

From that, the correct circuit diagram for your car is 518-05/61a.
I have this, but it's not a good quality copy, so I have tweaked the image as best I can for the Bitron/keypad side of the circuit...
518-06_61a_BitronpagePicasa.jpg
As Mike has said, it differs from the later circuit of Gabor's, in that his pin 10 of the Bitron goes to pin 40 of ECU, while yours (as in the circuit above) goes directly to Gnd. #620 (the Inertia Switch) was deleted on later diesel vehicles (including yours), although Gabor shows it just for information. The connection 9-->20 is continuous, no switch.

The image above is correct, but not easy to read, so you could continue with Gabor's circuit for most things, especially the connector numbers.
_______

You say:

Ingognition OFF - pin 14 powered OK
Ingognition OFF - punctured wire 7 to check power but then relay click
This sounds a bit odd; puncturing the wire should not in itself cause the relay to close, unless there is an intermittent connection somewhere. Could you check this out?
Turning Ingognition ON - something clicking inside relay
Relay(s) should click once and stay on. Should not be repeated clicking. Connection?
Pins 4,5,13 i checking with unpluged ECU connector.
I grounded 45 pin in ECU to make relay click then checked pins: 47-powered, 48-powered, 49-NO powered.
Looking pins 49<->13 and there is continuity so don't know why 49 is not powered. Also replaced to another bitron and same result.
You will have the EGR valve/solenoid (#437), but I'm not sure where it is located on the 2.1 engine.
47,48,49 should all power up, and show voltage, if 4,5,6 on the Bitron are powered.
Might be worth looking at the EGR valve or its connections.

______________

" Going next i dont have power on 14 pin in Anti thief kbd and no continuity between Diag box C1 and C2 with inj Ecu. In circut diagram all of these going throught "Black square number 10" what was this? "

Anti-theft keypad should have one IGN switched live (13), one that goes live when Bitron relay closes (14), and two data connections to the ECU (3,4)....the code to start is stored/checked by the ECU, not on the keypad.
Pin 3 on the Bitron relay MUST be supplying the keypad for it to operate and allow a start.

The coloured squares on Gabor's diagram (white ones on Citroen's) are intermediate connectors.
Gabor black square = black connector; 10/3 means it's a 10-way connector, and pin 3.
On Citroen's diagrams, the colour of the connector is given by the Letter......eg 17N = 17 way connector, Noir (=Black).
_________

The lack of power to the Keypad could be a main cause of the problem. It should be getting two +12 supplies (13, 14) to operate correctly. Reg+Green LEDs does indicate a keypad/ECU fault.
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Re: Citroen XM - lost contact with ECU

Post by Mateusz »

Right, 7522 that's my painted number.
This sounds a bit odd; puncturing the wire should not in itself cause the relay to close, unless there is an intermittent connection somewhere. Could you check this out?
I checked this by light bulb (-)connected to negative clamp in car battery, (+)punctured wire 7. Then its making click and bulb light on very poorly.
Relay(s) should click once and stay on. Should not be repeated clicking. Connection?
Now its hard to say that was one or two click. but pins 4 and 5 are powered so mean its keep
You will have the EGR valve/solenoid (#437), but I'm not sure where it is located on the 2.1 engine.
Maybe this? Dont have better pic. to this stuff going two pressure tubes
Image
Anti-theft keypad should have one IGN switched live (13), one that goes live when Bitron relay closes (14), and two data connections to the ECU (3,4)....the code to start is stored/checked by the ECU, not on the keypad.
I was checking this before and 13 was powered but 14 was dead.
tomorrow i check again what happend with 14 when 3 is powered
The coloured squares on Gabor's diagram (white ones on Citroen's) are intermediate connectors.
Gabor black square = black connector; 10/3 means it's a 10-way connector, and pin 3.
So its black 10 way connector? I might know which one. Its very strange connector screwed together like bolt. I check him too
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Re: Citroen XM - lost contact with ECU

Post by Hell Razor5543 »

The RPO is four or five numbers long followed (typically, but not always) by two letters. The numbers are used to calculate the date the car came into existence, and the letters are the factory code. For example, my C5 has the RPO 10045CJ, which means she was 'born' on 10th May 2004, in the Rennes la Janais factory;

http://www.citroen-ds-id.com/gen/Gen_Organr.html
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Re: Citroen XM - lost contact with ECU

Post by white exec »

" This sounds a bit odd; puncturing the wire should not in itself cause the relay to close, unless there is an intermittent connection somewhere. Could you check this out?

" I checked this by light bulb (-)connected to negative clamp in car battery, (+)punctured wire 7. Then its making click and bulb light on very poorly. "


That sounds OK. You grounded pin 7 via the light bulb, and got a dim lamp and a weak relay closure. Bulb acts like a series resistor. Sounds about right, though.

Do check out the keypad supplies tomorrow.

I can't confirm that that is the EGR valve/solenoid. Others here may know.
Best expertise on XM 2.1 is on club-xm.co.uk, as I said at the start! - but doing our best...
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Re: Citroen XM - lost contact with ECU

Post by Mateusz »

I got it. All these problems caused this 10 way connector. Some of pins are cambered. Quick straightening and all back to live :)
Btw. appear new problem with abs relay but this is for new topic, now in xm.co.uk as you recommended earlier.
Thank you so much for your help and patience, your advices helped me a lot and learned how to read circuit diagrams ;))
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Re: Citroen XM - lost contact with ECU

Post by white exec »

Well done in tracking the problem down to that 10-way intermediate connector.
(It is the one where the Intertia (crash) Switch used to go, before it was deleted. The link is essential to allow the injection ECU and injection to function.)

XM is a car guaranteed to exercise the brain cells when it comes to electrics. Fortunately, we have detailed circuit diagrams and technical info for it, and all model variations.

Look forward to seeing you club-xm, where you'll find lots of help and information.
Getting the car mobile again is a great Christmas present, so well done for sticking with it.
Keep an eye on that connector!

\:D/
Chris
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Re: Citroen XM - lost contact with ECU

Post by white exec »

Well done in tracking the problem down to that 10-way intermediate connector.
(It is the one where the Intertia (crash) Switch used to go, before it was deleted. The link is essential to allow the injection ECU and injection to function.)

XM is a car guaranteed to exercise the brain cells when it comes to electrics. Fortunately, we have detailed circuit diagrams and technical info for it, and all model variations.

Look forward to seeing you club-xm, where you'll find lots of help and information, including ABS.
Getting the car mobile again is a great Christmas present, so well done for sticking with it. \:D/
Keep an eye on that connector!
Chris
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