Xantia engine wont start - bad electric contact when cold - Solved

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lancia58
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Xantia engine wont start - bad electric contact when cold - Solved

Post by lancia58 » 10 Jan 2015, 12:49

Yesterday I could not start the engine. I hooked a Lexia and I could not communicate with the the engine ECU ( at the same time it did communicate with the AL4 automatic gear ECU ) . I suspected that the ECU doesn't get the correct voltage, so I unplugged the engine ECU harness. As I don't have the wiring diagram I checked all the pins some of them showed voltage but none showed 12.5v all where not more then 11.5V. As I have nothing to do without the wiring diagram of the car I plugged the ECU harness connector back to the ECU and voila the Lexia could communicate with the ECU and then one turn of the starter and the engine started. I have to mention that when the engine started jumpers were connected to my C4 to the Xantia since the battery was low. Happily I drove the Xantia and today at the morning I could not start the Xantia again. I have to add that it is very could less than 8 degrees Celsius. I noticed that on top of the engine problem the power door locks are not working. From my experience when the temperature rises to around 13 -14 degrees Celsius it looks the power locks work. It looks like there is a bad electrical contact that is depends on the temperature.

Any help is welcome

Thanks

Zohar
Last edited by lancia58 on 10 Dec 2017, 20:40, edited 1 time in total.
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Hell Razor5543
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Re: Xantia engine wont start - bad electric contact when col

Post by Hell Razor5543 » 10 Jan 2015, 13:43

There is a known issue with the battery leads beginning to fail due to age. I wonder if that could be your problem?

viewtopic.php?f=3&t=38273
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lancia58
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Re: Xantia engine wont start - bad electric contact when col

Post by lancia58 » 10 Jan 2015, 15:01

Hi

If the battery leads failed how comes that the starter spins freely and not slughisly like a low battery in case the leads fails ?

Thanks
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Hell Razor5543
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Re: Xantia engine wont start - bad electric contact when col

Post by Hell Razor5543 » 10 Jan 2015, 17:25

Ok, so it isn't likely to be the leads.
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lancia58
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Re: Xantia engine wont start - bad electric contact when col

Post by lancia58 » 10 Jan 2015, 17:53

Hi

Just came back after succeeding in starting the engine, following is what I did:


1) I took apart the ECU and check with Digital Multi Meter that the pins of the ECU connector are soldered well. I did this inside my apartment a fact that warmed up the ECU to around 20 degrees Celsius
2) I used a women hair drying fan
3) Warm up the positive battery terminal
4) Warm up the fuse box under the steering wheel
5) After this I started the car and the engine immediately came on no more than 1 to 1.5 starter turns

As I did all the above steps at one time I do not know which of them temporally solved the problem. I am sure this problem will reappear. From all the above steps I think step 4 did the job. The car is fitted with an after market remote control and automatic windows lifter. Although the car is originally fitted with remote control the guys that installed the window lifter bypassed the original remote control. To say the least they did a bad job as the wires are not soldered and they cut the original wiring. I plan for a long time to remove the after market windows lifter and re-wire to the original.

Anyway I need the wiring diagrams of the car for both tracking down the problem and re-wire to the original state


Thanks
Zohar
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Re: Xantia engine wont start - bad electric contact when cold

Post by GiveMeABreak » 12 Nov 2016, 12:26

Zohar - diagrams sent via email. :)
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white exec
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Re: Xantia engine wont start - bad electric contact when cold

Post by white exec » 12 Nov 2016, 13:16

Apart from battery connections degrading with age (replace them with brass clamp type, and clean up the heavy cable strands back to bright metal), the multiway connector pins at the emgine ECU are also known to acquire dirt over the years. With battery disconnected, unplug, and use a good quality aerosol contact cleaner on both halves. Unplug and plug in several times to shift any residue.

Over years of use, all the electrical connectors and relays at the very front of the car can show dirt and oxidation on their pins/blades - especially if the car has had use in dusty or wet conditions.

Also worth checkimg out Ground connections to bodywork: unbolt, clean up and bolt down tight. You may even find that the area on the body around the threaded hole was factory-painted! Worth cleaning this paint off, back to clean metal, so there is a better ground contact. Protect the ground connection with a dob of grease after you have bolted all the clean bits down.
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lancia58
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Re: Xantia engine wont start - bad electric contact when cold

Post by lancia58 » 17 Nov 2016, 05:25

Hi

When I warm the passenger compartment fuse box with a hair fan for couple of minutes all is OK and I can start the car, so I guess it is someway related to the fuse box or some other connector that is near the fuse box. The fuse box is not detachable , it is not the one that is frequently found in Xantia's but the same one as in a Berlingo. I noticed that when the engine wont start the immobilizer sign in the instrument cluster ( a key like Orange icon ) is not lit. That means that somewhere in the immobilizer circuit chain there is a failure due to low voltage. Fuse #9 powers the CPH that in turn is part of the power lock , so I guess that there is a bad electrical contact between fuse #9 and the connector that plugs onto the CPH.

Zohar
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Re: Xantia engine wont start - bad electric contact when cold

Post by xantia_v6 » 17 Nov 2016, 06:14

Is this the same car described in this topic? viewtopic.php?f=3&t=53866&start=15
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lancia58
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Re: Xantia engine wont start - bad electric contact when cold

Post by lancia58 » 17 Nov 2016, 09:47

Yes , but I did some more research and now I am more focused on the source of the problem,

Zohar
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Re: Xantia engine wont start - bad electric contact when cold-Solved

Post by lancia58 » 10 Dec 2017, 19:39

Hi

Finally I had the time to track it down. I took the glovebox out and heated with a hair fan the CPH ( Texton box ) and immediately the immobilizer functioned and I was able to start the car. I re-soldered all the connectors and the chips inside the box but it didn't cure the problem. Then I took out the printed circuit from the black box and put my finger on the CPU in the box ( a big Texton chip ) in order to heat it ( up to 37 Celsius ). Gradually the CPH started to function till it was completely functional. As I removed my finger from the chip it gradually stopped functioning. I ordered a used CPH ( Same Texton model ) plugged it in and it worked in cold temperatures. As the immobilizer code in the EEPROM that is mounted on the printed circuit is different than the one in the none-functioning CPH I switched the immobilizer icon in the instrument cluster is blinking and the engine won't start. All I have to do now is transfer the EEPROM from the none functioning CPH to the one I ordered to make the immobilizer work again, or reading the EEPROM and re-program the ignition key with my Lexia.

Zohar
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lancia58
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Re: Xantia engine wont start - bad electric contact when cold - Solved

Post by lancia58 » 25 Dec 2017, 16:05

Hi

I switched the EEPROM and now all is good. Immobilizer is functioning in all temperatures and car starts immediately

Zohar
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Re: Xantia engine wont start - bad electric contact when cold - Solved

Post by CitroJim » 26 Dec 2017, 07:56

Gosh, that's an incredibly interesting problem Zohar! Fantastic diagnosis and solution! Well done =D>
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lancia58
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Re: Xantia engine wont start - bad electric contact when cold - Solved

Post by lancia58 » 27 Dec 2017, 16:14

Some of my observations regarding the problem

1) When the CPH is not functioning the Lexia can not communicate with the engine ECU, as I don't have the wiring diagram I guess that the communication is done via the CPH or the ECU power is controlled some how by the CPH
2) Even when the CPH functioned ( immobilizer was OK ) , when it was cold I had a harsh starting , now the car starts immediately.
3) With a good CPH it seems like the engine works more smooth/even
4) The problem in the following thread also cured with the new CPH box and no relay clicking anymore
viewtopic.php?f=3&t=46931
5) It looks like the problem of bad smell in the following thread also cured
viewtopic.php?f=3&t=36380

Regarding issues 4 and 5 above I can only guess that if the engine ECU power if fed via the CPH, it may be that the ECU voltage was a bit low ( didn't check it ) and the sensors values read by the ECU may be a bit wrong resulting in error in calculating the correct air to fuel ratio, but this is my guess and not a solid conclusion

Zohar
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Re: Xantia engine wont start - bad electric contact when cold - Solved

Post by CitroJim » 27 Dec 2017, 16:40

That's a real bonus when one fix also fixes two other faults Zohar :) That's just excellent!
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