C5 2.2 auto 'speed control' problem

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detheridge
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C5 2.2 auto 'speed control' problem

Post by detheridge »

Hi folks,
set off this morning and had only done a mile or so from home when the auto gearbox went clunk and the message 'speed control problem' flashed up - at which point the revs fell to zero.
While waiting for recovery, I restarted the car and everything was fine for a minute, at which point the same thing happned again. Sometimes the car will start and run for a minute or so before stalling, other times it just churns away with the engine light on and 'service' light on the dashbord. Not having anyone with a friendly Lexia to hand and not having sufficient spare cash for a (presumably) expensive diagnostics at an official Citroen garage, has anyone had this problem before (I certainly haven't with experience of four different C5s). Would a BSI reset help, or has something terminal happened? It's a 2.2 VTX+ auto estate.
Many thanks in advance,
David.

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GiveMeABreak
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Re: C5 2.2 auto 'speed control' problem

Post by GiveMeABreak »

Hi David

I think you already know that a diagnostic is going to be essential at this point to avoid guesswork. It may be something simple, but may not, hence the need to see what fault code (s) are logged against it, which there almost certainly will be. A BSI reset is not likely to do anything at this point, given that you have already said there was a mechanical clunk.

I would certainly not try to keep starting and putting it into drive until the issue is diagnosed as you don't want to cause further issues. It is possible that the pressure regulation electrovalve (s) are or have failed - but this is a guess at present of course. When was the gearbox fluid last changed?

Two things I would suggest in the interim - one is to update your profile on the left, as you have no location information and you haven't listed your model, year, engine info, which may help others determine if they are practically within distance to assist with the Lexia (as not all members who may be able to help have their details on the Lexia users list). And secondly, pop your VIN up here so we can ascertain exact specification of your vehicle.

A diagnostic at a dealer will likely be anything up to £90 an hour - which is not far off the cost of a decent kit (minus laptop of course), so I would certainly suggest getting your details up to date in case a member can offer to assist you with the diagnostic. We can help interpret any diagnostic codes as they relate specifically to your car afterwards.

detheridge
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Re: C5 2.2 auto 'speed control' problem

Post by detheridge »

Hi Marc,
Many thanks as usual for your insight and suggestions. I had a small service done (all oil changes) six weeks ago. The VIN is: VF7**************[VIN obfuscated, can be read by forum staff].
Regards,
David.

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GiveMeABreak
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Re: C5 2.2 auto 'speed control' problem

Post by GiveMeABreak »

Ok, for anyone wanting to chip in, David has a C5 II 5 DOOR ESTATE 2.2 HDi particle emission filter 175 6-SPEED AUTOMATIC GEARBOX, with the AM6 gearbox.

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xantia_v6
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Re: C5 2.2 auto 'speed control' problem

Post by xantia_v6 »

The mechanical noise was likely the transmission ECU going into limp mode and selecting the default gear without the normal cushioning, thus probably not indicative of the main fault.

detheridge
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Re: C5 2.2 auto 'speed control' problem

Post by detheridge »

Hi folks,
well I managed to get someone to bring a diagnostic box over to check the car - not a Lexia though.
The fault's in the engine and not the gearbox (when the engine stops providing power the gearbox goes into safety mode?), and the mech found an intermittent power supply to either the cam or crank sensor.
At a guess (and it IS a guess on my part) it's either the proverbial loose wire caused by the awful condition of Shropshire roads or a potential failure.
Just to be even more annoying, the car starts fine, but I daren't risk taking it out without the original problem happening again.
Any suggestions, tips and hints very welcome - do I need a new sensor or just an inspection ofthe wiring?

Thanks in advance,
David.

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EDC5
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Re: C5 2.2 auto 'speed control' problem

Post by EDC5 »

If your engine is anything like the 2.0 HDi then both the cam and crank position sensors are easily accessible on the left end of the engine.

I have replaced both on mine as I had noticed occasional faults recorded by lexia referring to the engine speed signal.

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Paul-R
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Re: C5 2.2 auto 'speed control' problem

Post by Paul-R »

EDC5 wrote:
02 Apr 2019, 17:55
I have replaced both on mine as I had noticed occasional faults recorded by lexia referring to the engine speed signal.
And did that solve your problem?

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EDC5
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Re: C5 2.2 auto 'speed control' problem

Post by EDC5 »

It has stopped any faults from recurring in the ECU fault log.

My point was the ease of which both sensors can be replaced if the 2.2 HDi is anything like the 2.0 HDi (which I suspect it is)

leithant
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Re: C5 2.2 auto 'speed control' problem

Post by leithant »

I think the crank sensor is on the gearbox end on the 2.2.

detheridge
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Re: C5 2.2 auto 'speed control' problem

Post by detheridge »

Hi again folks,
Success - it was the crank sensor after all. My local garage fitted a replacement and everything's works as it should once again (at least for the present!) and I'll let you know if there are any further repercussions.
Many thanks to all for info and assistance, and if anyone else has this problem, you now know the potential cause(s).

leithant
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Re: C5 2.2 auto 'speed control' problem

Post by leithant »

Had a look, and I can't see mine. I have a 2.2 with ZF tranny. It's meant to be under the thermostat housing I think. Anyone have a photo? Service box wasn't that enlightening this time.
PS Delete this if you want and I'll start a new thread.