P

P38Rc

Member
I bought a P38 4.6 GEMS which has gearbox fault showing. I have done reading on it but can't quite work mine out - hopefully someone will be able to suggest something else i can try to fix it for good.

Symptoms : After starting the engine the gearbox fault flashes up after around 5 seconds. It doesn't show up with just ignition on. When it has come up the gears don't show on the dash anymore and the sport button doesn't work. The gearshifts are harsh up and down and the car feels sluggish overall. The mirrors dip in reverse still (though don't appear to come back up, but i think this is probably a separate issue?).

Work so far: I changed the XYZ switch. I disconnected, contact cleaned and reconnected all plugs related to the gearbox that i could see. I have cleaned the alternator earths and added an extra direct wire from the positive to battery (voltage seems to show 14.2+ after this).

I changed the gearbox ECU which DID solve the problem, everything was fixed for a day of driving (roughly 30 miles) when the problem came back about 2 minutes into a drive, i stopped and restarted the car which removed the problem for the rest of that journey however it came back for the next trip as above.

I have another space gearbox ecu, but i am worried that i have 'blown' the other i put in so i'm cautious of changing it again until i don't think that will happen. Is that likely?

Any help would be gratefully received.
 
Engine running, in neutral, it shows in between the lines on the dipstick. I topped it to this level so it was a touch low before. Its red, not burnt!
 
Hmmm.....

Might be time to plug it into diagnostics and see what fault codes are on there, if it has done the same thing with two different ECUs then it must be an issue with the box or its sensors.

First and Reverse gear engagement is a mechanical link I believe and the other shifts are hydraulic based on output speed.....I'd get it plugged in and read the fault codes first, else all we're doing is chasing tails and urinating into a mild breeze!
 
That was the next plan - just hoped i had missed something obvious. Do the ecu's forget or get blown somehow? I'm just curious of why the ECU change let it work for a day before showing up the fault again.
 
Yep checked from cold! I actually think it had a bit much in, maybe 250ml which i have removed today.

The transfer box was apparently changed recentlyish, which connection is that? The big black plug on the back? I have disconnected and reconnected all of them so *think* they're all good. I will re-check.

It does shift into low range still, so i suppose it must still have the connection?
 
£60 at my well regarded local indy specialist for a code read and not until march 2nd! They're doing ok.

Does anyone know if the nanocom evolution can be used on as many vehicles as you like? I have 2 p38, one GEMS v8 and one late 2.5 DSE. I'd also like to know if could use it on a later v8 if i upgraded?
 
You can purchase unlock codes from BBS to unlock the other vehicles....not sure how much - £50 seems to ring a bell.
 
There's two things I'd look at before you spend anymore money.

First being the engine temperature sensor.

2nd, get the kick panel off from the passengers kick panel & check those white multi connectors hidden behind that panel. When these corrode, & they do, they give all sorts of problems with the EAS & Gearbox.
 
Thanks for the suggestions - i think i've just cracked it.

The plug connector behind the rocker covers wasn't clipped together fully - i'd found it looking tired last week so contact cleaned and pushed it back together with a cable tie for good measure (obviously just enough for one day). What i hadn't noticed was that its clip wasn't broken as i had thought - it just needed a bit more pressure to fully connect.

Maybe Hawkeye can wait for now - just the 3 other main faults to sort, i might need to make new threads however...

1) The brakes have a delay when pushed which is quite worrying. It doesn't seem to happen if you have just used them, only if there's a 5+ second gap between pushed. Hit the pedal, nothing really happens until they seem to 'catch up' with you and then appear to operate right (maybe a little weak however). Does this sound like accumulator or dodgy calipers?

2) SRS light is on after i had shorted the fusebox blowing the interior 60Amp fuse, after replacement all other warning lights/messages stopped apart from the SRS now stays on. I think it probably logged the fault as a blown fuse now won't self clear as its an early car?

3) After stupidly trying to open the sunroof on a frosty sunny morning the passenger side sits about an inch lower and it gets stuck trying to open in both slide or tilt functions.
 
If the pump runs on every 1-2 pedal pushes, the accumulator is fecked.....easy change.

SRS will not clear without diagnostics, needs to be plugged in for that one!

No idea on the sunroof, check the mechanism is clear of obstructions and that the glass seal isn't fouling on anything as it tries to go up. Sometimes in the cold, the seal freezes to the surround, as the sunroof either drops down to open - pulling the upwards or if opened to tilt upwards - the seal is pulled downwards.
 
Nanocom modules work for all 3 variants apart from the engine one and if you don't have the EDC module only one of the ABS modules will work for you.
 
Grrrrrr said:
Nanocom modules work for all 3 variants apart from the engine one and if you don't have the EDC module only one of the ABS modules will work for you.
Click to expand...

Nanocom for the P38 covers both Wabco C and D. C is ABS with two wheel traction control up to 1999. And D is ABS with four wheel traction control from 1999 on. ;);)
 
P38Rc said:
Thanks for the suggestions - i think i've just cracked it.

The plug connector behind the rocker covers wasn't clipped together fully - i'd found it looking tired last week so contact cleaned and pushed it back together with a cable tie for good measure (obviously just enough for one day). What i hadn't noticed was that its clip wasn't broken as i had thought - it just needed a bit more pressure to fully connect.

Maybe Hawkeye can wait for now - just the 3 other main faults to sort, i might need to make new threads however...

1) The brakes have a delay when pushed which is quite worrying. It doesn't seem to happen if you have just used them, only if there's a 5+ second gap between pushed. Hit the pedal, nothing really happens until they seem to 'catch up' with you and then appear to operate right (maybe a little weak however). Does this sound like accumulator or dodgy calipers?

2) SRS light is on after i had shorted the fusebox blowing the interior 60Amp fuse, after replacement all other warning lights/messages stopped apart from the SRS now stays on. I think it probably logged the fault as a blown fuse now won't self clear as its an early car?

3) After stupidly trying to open the sunroof on a frosty sunny morning the passenger side sits about an inch lower and it gets stuck trying to open in both slide or tilt functions.
Click to expand...
Hi can you remember where the multi plug behind the Rocker cover was

I am working by feel as it’s a pain to see.

Is it middle, drivers or passenger side ?

thanks in advance
 
If it’s the round one one with around 15 pins yes.

the location of ‘behind the rocker covers’ where the OP said they managed to reclip the connection seems a little off on location if it’s the one under the coolant. GM

have the same problem.

no message centre Indication of gear. Gearbox fault on start up.
No sports and no kick down.

have a 2nd hand eat ecu on the way. All works fine other than that.

Warning occurred after a head gasket replacement. Then appeared directly after its MOT a day later !

I guess that’s a lucky break !!
 
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