"gearbox fault" illuminated.

Hi All
I've a P38 1997 Autobiography 4.6..i keep getting on dashboard " gearbox fault" combined with loosing P D etc..also sport mode light extinguishers and the car goes very sluggish ..almost as if in high gear constantly. Is this another common fault on a P38 and if it is any ideas what causes it and how to repair it. Thanks.

Dead battery will give you lads of fault readings, but that's as far as my knowledge goes

as dopey said, first place to look is low battery volts due to a shagged battery and/or a faulty alternator. If it's not that, you need to get the fault codes read. The sluggishness is due to it going into limp home mode.

Thanks...interesting i have recently put a new battery on the car and this came on

deltic1997 said:

Thanks...interesting i have recently put a new battery on the car and this came on

Click to expand...

There seem to be a lot of duff new batteries about these days. The P38, petrol or diesel likes plenty of volts, the biggest battery you can fit is 135AH 1000CCA, it cures all manner of funny messages if all else is OK Also worth checking the under bonnet fuse box for signs and smells of burning and battery/engine earth connections.

Get the Multimeter out and check for engine off voltage - should be around 12.4 to 12.8 lower than 12.3 battery is low...

Start car and get a willing assistant to hold the accelrator at 2000rpm- check voltage again, 14.4 to 14.8 is good, 14.3 or lower than this, either the battery is dragging the Alternator output to low or the Alternator is on its way out...IMHO

Had similar when transfer ecu was faulty, even lost gears completely sometimes

If you don't know anyone with P38 diagnostics, you could try a call to Jamesons 4x4 in Summer Lane, 0121-333-3556.
They know P38's inside out and won't rip you off.