D4 gearbox fault, now stuck in limp mode/3rd gear.

[Petsos]

Hi there,

Purchased my 2010 D4 2.7ltr TDV6 (currently 180k on the clock) late last year intended for the trip from Perth to Coral Bay over Easter which we have just completed. Had the car looked over by a reprobate mechanic with oil and filters changed before we set off. We have been super happy with the car so far and completed the 2200km trip with no hassles, towed a small caged trailer with camping gear and did some beach driving nothing that the car couldn't handle... :thumbsup:

Upon return to Perth while dropping off the trailer, the gearbox fault came up on the dash and threw me into limp mode stuck in 3rd gear. I have tried a hard reset and the fault still remains and still in limp mode?

Codes reading;
Engine code: P0237
Trans code: u2023 and u0402

Not sure if anyone has experience anything similar or can point me in the right direction?

Appreciate your help!!



150398

[Graeme]

I expect the engine's fault has triggered the gearbox fault. Start with checking that the wiring to the MAP sensor is intact.

[justinc]

Or the MAP itself has packed it in. ALSO check your brake lamp fuses...

[Petsos]

Thanks for the feedback gents,

Checked the MAP sensor and wiring, seemed in working order gave it a clean reinstalled. No difference. I might add the engine it self is okay no loss in performance etc just gearbox stuck in 3rd?

Code P0237 is the turbo boost sensor? Where are these located and are the accessible to inspect?

cheers

[Eric SDV6SE]

It is odd that a turbo boost error code locks the gearbox in a gear. Normally in limp mode all gears are enabled , just the engine performance is restricted.

im sure you’ve done all the other std checks re intake ducting, checking for leaks etc. have you been able to reset / clear the error code?

conversely it could be a transmission error that has caused an engine error code, do you know the last time the transmission fluid was changed (if at all)? At 180.000km I’d expect that, if not changed previously, the fluid is past its lifetime, the valve body and it’s solenoids and the corresponding valve cylinders would be gunked up, causing shift problems and not allowing the clutch packs to be disengaged properly...

a full fluid flush and Sonnax valve body rebuild kit does wonders...

[Petsos]

I have done checks to the best of my knowledge, everything seems okay. Tried the resetting/clearing codes by disconnecting the battery and touching terminals, hasn’t seemed to work. Drove it to the closest mechanic to check for codes, supplied me with above codes but did say he said he couldn’t remove the codes with his reader?

I just went through previous service documents and receipts , no mention of any major gearbox work/maintenance. My mechanic who looked over before the trip did say looks like nothing has been done as standard sump pan still in place and will be worth looking into?



:wallbash:

[Eric SDV6SE]

Definitely, I haven’t checked what the transmission codes are that you posted, but worth looking into. AFAIK the order of precedence in error reporting is the P codes, then anything below that. P is power train module and that includes engine, so the first code logged is the best starting place.

You will need either a mechanic that can read and clear codes, or a JLR service centre to resolve.