P 38 guru needed

[Rocket88]

2.5 with auto box has strange issue. Box behaves normally 90% of the time, but for no apparent reason occasionally loses top two gears, and will then stall at low speed. The gearbox warning light appears. Re- starting the car clears it, and it drives fine. Fluid is clean and at the correct level. When it does happen, sport mode disappears. Any ideas?

[goosey]

A tired battery on these can cause the gearbox ECU to play up, dont know why but it’s the first thing that suffers when the battery voltage is too low 

also corroded terminals and connections can cause gearbox issues 

From what I can remember there is a big round connection under the header tank which can get water in it also check your fuse box for corrosion

 

 

[Minimad5]

Had it plugged in for any fault codes stored ?

Goosey is right about them throwing a wobbler when the battery drops.

Wonder if it isn't shifting into first, hence the stalling .... I could be wrong but try disconnecting the battery for a wee bit so it re-learns / forgets the stored fault (I could be wrong here)

Sorry for lack of advice, but following as my mates just got himself a P38 2.5d Auto, so this may come in handy for him.

[Rocket88]

Battery is in fine fettle… will

check connector

[goosey]

From what I remember when the transmission goes into limp mode it locks itself in 3rd gear and you lose sport mode 

I may be wrong but I’m sure there is a way of checking error codes on the mileage display 

[goosey]

23 minutes ago, Rocket88 said:

Battery is in fine fettle… will

check connector

Start it from cold and use a Multimeter to see how much the voltage drops.

Has it had a “hot start kit fitted” ?

sorry if it sounds like I’m teaching granny to suck eggs 

[timolloyd]

@Cooper1 @Broadsword may be able to advise also.

[Broadsword]

Assuming the battery is ok (and they are very fussy on this front, they do not like modern calcium batteries, proper lead acid batteries make a difference because the alternator can actually charge one of those), have a look at all ground points, and also the infamous XYZ switch on the side of the gearbox. Does the light on the gear selector definitely illuminate constant on drive when you select it? When the XYZ goes iffy (usually in wet conditions) you will see the gear position selector flickering (corresponds to flickering on dash screen). If it is doing that try a good blast of electrical contact cleaner direct at the XYZ switch (can be done by reaching in from passenger side engine bay).