Citroen AX (1987 -1997) - 95 1.0 Speedo problem

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Tue 27 May 2008 12:43
95 1.0 Speedo problem - V
Wonder if anyone can help with this - my AX has recently developed an intermittent speedometer problem. Now it seems when i have driven between 10 and 15 miles, the speedometer drops to nothing and the trip and odometer stop working. this doesn't seem to coincide with changing gear or change in speed or anything like that. It doesn't help if i stop and restart the car, but it does always seem to work from cold. the garage had a nosey but couldn't tell what the problem was. Any suggestions would be appreciated - seems like the garage want to start replacing parts until they happen to find the right one, but I would prefer to work out which part it's most likely to be and get a mate to fit it to save a few quid.
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Tue 27 May 2008 14:07
95 1.0 Speedo problem - Screwloose

The centre pin of the gearbox-mounted vehicle speed sensor should be producing an on/off 5 volt pulse when the wheels turn.
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Tue 27 May 2008 14:33
95 1.0 Speedo problem - V
hi, cheers for your reply. I'm afraid i'm rubbish at this stuff though - do you mean I should get that tested, and if it's not producing that pulse, it's that senor that needs replacing?
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Tue 27 May 2008 14:41
95 1.0 Speedo problem - Screwloose

Yes.

If you can't test it yourself - and your garage doesn't sound very clued-up - then you need to find one of the fast-disappearing diagnostics specialists that can trace this sort of fault.
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Tue 27 May 2008 14:59
95 1.0 Speedo problem - V
Cheers, I'll give that a go then
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Wed 10 Sep 2008 14:35
95 1.0 Speedo problem - V
Seem to have it fixed now, so just thought I'd pass on what sorted it in case anyone else has the same problem.

I got a garage to have a look and they ordered a new gearbox mounted sensor. when it arrived from the citroen dealer, this wasn't the right part, as it had different connections to those on the original part. The garage gave up, so I went to a Citroen dealer myself to ask about this.

Their lists gave this incorrect part as being the right one for an AX (this costs around £70+), but they guessed it might be a differnt part for around half the price. They fitted this for me, which was the correct part, but told me this hadn't solved the problem, and I would need the gear box stripping as the plastic cog which transmits teh motion to teh sensor wasn't doing so.

As i left the garage the speedo etc wasn't working, but about 100yards down the road I think I must have driven through a puddle of holy water as it started again, and several hunderd miles later, touch wood, it's still working perfectly. Best guess is that the plastic cogs which transmit the motion between the gear box and sensor were worn, and replacing the sensor was just enough to allow the cogs to catch and for it to work again. Not sure if this will carry on working indefinitely, but certainly seems fine for now.

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