Electronic gremlins

[Aw908590]

Hi all,

Hopefully some of you more experienced X5 owners may be able to give me some pointers on a few issues I'm having with a new purchase.

I've recently bought a 2003 4.6is and I'm having a few issues with some of the electrics and sensors.

First off I'm getting the trans fail safe program warning which having scanned the forum seems to be quite a common issue. I will check the battery power as well as Fuse 5 which seem to be regular checks, but wondered if anybody else had any pointers?

Secondly I'm getting the tyre pressure check warning come up, but having checked them they are all fine? Could this be a faulty sensor or just a reset job?

The rear PDC seems to have a mind of its only and beeps continually when you select reverse, no matter how far away you are from an object? The car has a tow bar fitted and I wonder if this could be causing an issue?

Just thought I would ask for some help before enlisting the help of the local specialist!

Thanks guys

[Horizon]

Hi and welcome to the forum
Trans fail safe can be anything from a faulty fuse to a knackered box. As mentioned, get the codes read.
The PDC defaults to a continuous tone when reverse is selected when there is a fault, usually a dead sensor.
With ignition on and in reverse listen close up to the sensors, they should make a clicking noise, if not they are suspect and need changing.
Your indie will be able to diagnose this whilst in for the trans fail safe problem too.

[X5Sport]

If the towbar has the dedicated electronics then it should disable the rear PDC when a trailer is connected, but could cause issues if no trailer 'on the hook' and the towball in place.  Non-OEM/dedicated wiring can cause problems though.  Otherwise, yes, faulty sensor is the usual cause.

Richard

[Aw908590]

Thanks guys, will book it in to the local specialist for diagnostics I think.

The trans fail safe is a strange one though as when the warning comes up, if you turn the ignition off and then re start it the warning doesn't come on again. It kicks down fine and gear changes are all smooth so I'm hoping it is an electrical issue rather than a box issue. Fingers crossed anyway!!

[Steamyrotter]

Sounds like a supply issue...
Battery, Alternator, FSR???

If it was gearbox you would lose all drive or have some strange behaviour..

Quick search on here will show you many things happen when the battery is a bit suss.

[Boatybob]

Sounds stupid but I find too much muck on the sensors causes your problem. A clean up often solves it.
BUT I was here for the Tyre pressure warning. Gone off three times in the last week but a pressure check shows no problems. Any clues on this would be helpful.

[X5Sport]

The TPS uses the ABS system to count the wheel rotations and if one wheel is turning at a different rate then the system thinks there is a flat tyre.  Have you got a more worn tyre on any one wheel?

Richard

[Denis O]

My 2003 4.6 actually had sensors in the tyres. I found out when, after fitting metal dust caps, I tried to get them off and buggered the valve. The car had to go to the stealer to have a sensor replaced.

Sensors are colour coded and there is the option of 2 different colours. The dealer doesn't know what colour until the tyre is off.

Sensor was about £100 and then diagnostic time to set everything up.

[X5Sport]

I believe only the V8's had that system, and possibly just the 4.6/4.8 though why just them I don't know.

Richard

[CondorX5]

I *think* it was only used on one of the 4.6 models - the sensors in the caps are powered by a battery I believe and replacement ended up being silly money for the cap.  Luckily sense prevailed and the system was only used briefly - the 4.8 models have the rolling radius type deflation warning, much less hassle and expense.