Eugene p123
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Hi guys I think it’s a 95/96 p38 , I cannot get the speedometer to work any suggestions?
Thanks
Thanks
95/96 p38 speedo not working
- Thread starter Eugene p123
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Datatek
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The speedo is driven by the ABS sensors, so it could be the ABS ECU, the BECM, the instrument cluster a bad earth or corroded connectors. Does the ABS light go out when you drive the car? Diagnostics might help narrow the problem down.
doriz
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Dunt the cluster loom run through the drivers footwell, start there.
Eugene p123
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Abs light goes out and new abs sensors replaced and new becm fitted , diagnostics says no abs faults
Hi I'm new to this. I have a similar year p38 doing the same. No abs faults on diagnostics or dash. Abs light goes out when you drive. Reconditioned becm fitted from Callrova based in UK. Any suggestion. Was having lots of problems electrical and becm cured nearly all of them. I'm down to the speedo the last one.
Datatek
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I don't think there is any such thing as a "new BECM", why was it changed?
No ABS faults, leaves you with an instrument cluster problem, bad earths or corroded connectors.
What diagnostics do you have? With NANOCOM, you can see the road speed which will tell you that the signal is coming out of the ABS ECU. The actual speedo can fail.
Datatek
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That leaves you with an instrument cluster problem, bad earths or corroded connectors. The actual speedo can fail. Does the mileage increase in the digital display when you drive it?
If you end up having to swap the instrument cluster, don't forget that if it has higher mileage on the replacement than the original, the memory in the BECM will update to the higher mileage.
@Datatek The milage does not increase on the digital display as ive been keepin an eye on it. Im confident ive ruled out the abs/abs ecu. Originally the car had severe electrical issues. Wipers on full time, no windows, no sunroof, headlights on with key out. But a reconditioned becm sorted nearly all. I had it down to 3 faults. Abs light which was a pressure switch which is now fixed. No fuel gauge which a sender unit sorted. Just the speedo now.
Datatek
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Sounds like you have had a problem with damp in the car. Can you see the speed on diagnostics? If the mileage doesn't increment, I would say the problem is between the ABS ECU and the BECM or the BECM and the instrument cluster.
RangeRoller dt
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Pssst….don’t say J**p
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Mileage is interpreted by the instrument cluster as 8000 pulses from the ABS ECU per mile (4972 per km). If you can see the road speed on diagnostics but the milage isn't increasing, I'd suspect the cluster isn't working..... Or at least it's having trouble interpreting it's pulses. It's not hard to remove, maybe it needs a good clean too.
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On my MY2000 4.6 the speedo stopped working because of an alternator fault.
It showed up after the vehicle went over a large pothole. The speedo & rev-counter would switch on/off at random.
Then the "Traction Fault" and Gearbox Fault" messages would keep popping up.
The Alternator was changed and the fault went with it.
Probably not your issue but check for charging Volts and AC ripple on the DC maybe.
Tried an abs ecu today. No luck. I'm confident it's not an abs fault. It has to be a wiring fault or faulty clocks. Does anyone know the wire colour from the becm to the clocks for the speedo signal. I stripped out the loom today and yes was lying in some damp but all wiring seems good from becm to clocks.
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Here is the relavent page from the manual (I think).....
Doesn't show much (to me), but I'd guess the signals got to go down one of them... You could try them all?
Doesn't show much (to me), but I'd guess the signals got to go down one of them... You could try them all?
Datatek
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I'm not sure you will find a single wire for the BECM to speedo, I have not checked but I think the info goes on an 8 bit data bus that passes all info from the BECM to the instrument cluster. I could be wrong there.
