on starting my p38a the dashboard displayed Abs fault, then immediately displayed gearbox fault. I withdrew the key to lock the vehicle and unlock it again, on this action the dashboard displayed key code error followed by central locking motor clicking continuously. This all happened in a spate of seconds. she is a 99 t plate. can anybody HELP I would really appreciate some help!
zzr1200
Well-Known Member
P38's are very voltage sensitive, is yours a petrol or diesel?
Also may help if you state your location as there might be a member local to you who is willing to help....
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The central locking reciever. Radio, wifi, etc can affect it causing the becm to stay "awake" leading to battery drain.
Mine showed up gearbox fault, abs fault the alarm triggered. Did a drop test on battery and found 2 cellf were shot. Changed battery last summer and it still draind but only when parked outside certain houses
West Slope Rover
Well-Known Member
The rf unit picks up the radio signals from your keyfob when using it to lock or unlock the motor. Old units can pick up radio signals from other nearby sources and those signals keep the unit working and draining the battery in its activity.
I not tried. There is a temp fix of removing a wire from it. But as I say mine only affected when parked in certain places as only gets used at weekends, so try to park outside my house when ever possible.
To test for battery drain I think you disconnect the negative and put a multimeter between the cable and battery post and chect the ampage. Can pull fuses to see where the drain coming from
To test for battery drain I think you disconnect the negative and put a multimeter between the cable and battery post and chect the ampage. Can pull fuses to see where the drain coming from
Replacing the rf unit as the new ones supposed to be better. Think if you disconnect the blue wire from it it helps. Believe it is behind the trim on right hand side of the boot. As I say I not delved into it
dogsbody
Very senior member
I think that you've possibly got three issues.
A low / poor / undersized battery in a P38 can trigger all sorts of funny faults with the old fashioned electronics responding to the fluctuating voltage as if they were instructions and operating 'things' on the car. For some reason the gearbox fault warning seems to be one of it's favourites.
You then say that you're on your second battery which would make me suspect your alternator. An alternator makes A.C. current that is then converted to D.C. by the diodes in the back of it. If the alternator is weak it may not be charging your battery fully. If the diodes are faulty then you will not get a clean D.C. supply and again the car's electronics may respond to this at random.
Then you have the issue of where you park it. If the receiver for the key fob is picking up signals from almost anything (wireless door bells, automatic doors, some wireless broadband systems, something in some petrol stations etc.) around the same frequency then the car's main electronics (the BECM) will not 'sleep' and can flatten a poor battery overnight. Remove the top right hand trim in the boot, three plastic plugs and a screw hidden by the seat back. Find the little black box with a blue wire going up into the window. This is the remote's aerial. Disconnect this wire at the box. You will now have to stand close to the car for the remote to work but hopefully it will stop picking up the other signals.
However I still strongly suggest that you get your alternator tested and fit the biggest battery that will fit in the space.
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dogsbody
Very senior member
Get your alternator tested before you buy another battery just in case.
Then you could measure the space that you have, don't forget the height, note where you need the battery connectors and go to a battery specialist, not Halfords.
Sorry I can't be more precise but I'm a diesel driver and we use 100 amp+ batteries.
Then you could measure the space that you have, don't forget the height, note where you need the battery connectors and go to a battery specialist, not Halfords.
Sorry I can't be more precise but I'm a diesel driver and we use 100 amp+ batteries.
You can take the blue arieal cable off the RF unit, the distance the keyfob will work from will be greatly reduced, but if after removing it, the battery drain is fixed, it means it is time to fit the new type receiver that isn't so sensitive to stray radio signals.
You can fit a 1000cca battery which I think is the largest that will fit!
You can fit a 1000cca battery which I think is the largest that will fit!
Look in the FAQ section. It's all there.
