XSeries-forum

hi
Im getting the above on my 2002 e53 x5 70000 miles,coming on randomly altho twice when I have turned the air con on,the car has a new battery and is reading 13.9v across the terminals on tick over.I have read the ECU with an ODB 2 but there are no faults stored as the lights reset when the ignition is turned off.I am not convinced this is a component failure maybe a spike/drop in voltage triggering the fault?Anyone got any experience or suggestions?
Thanks

I hope you mean 13.9V ? Fully charged it should be 14.4 - 14.6V.

What does it read with the engine off and the car having been left alone for at least 4 hours? If you can, measure the volts on the jump starter points under the bonnet - means you can leave the car locked and it can go to sleep. If you leave the bonnet open (assuming it is safe to do so), or even raised far enough to keep it away from the alarm switch, then you'll get a value of the battery volts with little or no load on it.

The other thing to try is the delay between turning the key to Pos 2 and then you actually starting the engine. Wait until all the warning lights have cycled and see if that makes a difference.

cheers battery was reading 12.5 volts with no load(it was 13.9 running!),will try the starting procedure to see what happens

thinking it may well be a speed sensor..

Pass on the sensor, but the battery sounds fine with those figures.

may look at swapping the rear sensors over as the drivers side also supplies the signal for the speedo which is ok when the fault occurs.So looks like that one is ok, if I swap them over and the speedo plays up when the fault occurs it will be that sensor.If the fault remains the same with out speedo error it would eliminate the two rears and then would need to look at the two fronts,hope this makes sense

[quote=""strummer""]may look at swapping the rear sensors over as the drivers side also supplies the signal for the speedo which is ok when the fault occurs.So looks like that one is ok, if I swap them over and the speedo plays up when the fault occurs it will be that sensor.If the fault remains the same with out speedo error it would eliminate the two rears and then would need to look at the two fronts,hope this makes sense [/quote]

I thought the sensors were different either side?

[quote=""mobilejo""][quote=""strummer""]may look at swapping the rear sensors over as the drivers side also supplies the signal for the speedo which is ok when the fault occurs.So looks like that one is ok, if I swap them over and the speedo plays up when the fault occurs it will be that sensor.If the fault remains the same with out speedo error it would eliminate the two rears and then would need to look at the two fronts,hope this makes sense [/quote]

I thought the sensors were different either side?[/quote]

not as far as I know? anyone confirm?

Edited - wheel sensor, not gearbox output pulse generator/counter.

hmm,I have seen reference to speedo reading being taken from drivers side rear wheel speed sensor,I think that was on the v8,so perhaps different?

[quote=""strummer""]may look at swapping the rear sensors over as the drivers side also supplies the signal for the speedo which is ok when the fault occurs.So looks like that one is ok, if I swap them over and the speedo plays up when the fault occurs it will be that sensor.If the fault remains the same with out speedo error it would eliminate the two rears and then would need to look at the two fronts,hope this makes sense [/quote]
unless your car is a left hand drive, the speedo is off the passanger side rear wheel sensor

come to think of it I think most of the things I have see have been yank,so it is worth swapping the rear sensors over to see if it effects the speedo? the rear sensors both have the same part number according to RealOEM.com

they do but speedo on uk car is passanger side rear, there about £92 off bmw, but the cheap sh*t ones on ebay are no good and if you get a dud you dont know if youve cured it, by the way they wont just slip out you will have to dowse in wd40 and carefully lever them out or they will snap off in the car and need drilling out. how are you with a multi meter as you can test the wheel sensors from the comfort of the abs unit under the bonnet in the time it would take to remove the rear wheels!

thanks for the info,appreciated,can wield a test meter a bit,how do I test from the abs unit?where is it? Should say the fault is intermittent so will it show up using the meter or do I need to get the codes read?

hmmm intermittant the worst kind, myn had no speado working varios dash light etc..so i undit the connector to the abs unit big black coneector with 20 or so wires to pins, all pins are numbered, google it and you find what pins are which sensors eg pin 13 and pin 20 are front drivers etc(that just e.g it will be different but you get the idea) then go between each pair on either ohms or continuity cant remember and im a spark lol, anyway i got like 0 ohm.0 ohm, 0 ohm and one that read 897 ohmm so i guessed that was the knacked one and it was the rear pass side that had the dodgy reading