I took my car in for a diagnostic check for a warning light with the gearbox. Apparently the diagnostic came up with the code POO46 which means turbo/supercharger boost control solenoid, circuit range performance.

How bad/expensive is that?

The diagnostic test was at a gearbox specialist, so they had no idea themselves.

 

It may be as little as a loose or chafed wire but otherwise points to a solenoid... well worth a search on the .co.uk forum - but make sure you put in P0046 (zeros, not letter O). Deciding whether it's a transient, or if not then diagnosing from there sounds a bit hit and miss but don't panic.

 

Turbo Boost solenoid is the electronic valve that controls the Wastegate ( petrol engine) or the variable vanes (VGT on diesel "your case")

It controls the maximum boost you can have in your boost circuit (std and overboost )

A faulty circuit could be potentially dangerous because you can have "overboost"

If the circuit it's properly working on "safe" mode (forced lower boost pressure than std) the problem is not dangerous except poor engine performances

The problem could be caused by
A: damaged cables or faulty connectors (time spending but easy to solve)
B: blocked variable vane turbine (time spending and should be expansive to solve)

Check the air intake boost to have a rough idea on that

 

Thanks for the replies. From what i have read when searching the actual code P0046, it is more likely to be electrical than the actual turbos, particularly as I am getting normal mpg and performance.

 

in order to see which are the cables involved in this problem you have to start from the turbos

On pressure attuator there is a little vacuum tube
This tube arrives in a solenoid valve that is cabled to the solenoid attuator ( in modern engines and your is this case the engine Ecu is in charge to control the duty cycle of this valve)
so check the connectors and cables that goes from the solenoid (s) to the ECU
This way you could solve the problem (if you say that are the cables)
If you drive normally you won't see differences, forcing the engine you could have an "uncontrolled overboost" due to the unserviceable VTG control
ciao

 

I have phoned the garage and booked the car in. At least I can now give them the codes.

 

Well the result back from the garage was that nothing can be found with the turbo/solenoid or wiring after a visual check, further diagnostic and test drive. They concluded that since I can find no performance issues that the codes are from the memory and they have not been deleted at a previous visit to a garage. It last service was not at a Jaguar dealer.

 

Their explanation of the origin of the code could hardly be less convincing.

 

agree with jag V8

 

Well I have been to a gearbox specialist and a reputable garage who do classics and I have never had any problems with them, and neither can trace the faults the code allude to. When I got the car it was showing a warning light for the airbag which was sorted with a refurbished ECU. I have also had an ABS warning message flash briefly on start up. The car is running fine. I dont really see what else I can do

 

I'm also not sure what else you can do, except.... you said it was a "warning light with the gearbox" - which light is that? (Maybe my car doesn't have one?) I'm especially puzzled as P0046 looks like it ought to be a MIL (aka CEL).

I suppose you'll anyway keep an eye for it happening again - please say if it does!

 

Sorry, when I say warning light I mean a warning message comes up on a panel in the dashboard. For the gearbox it said 'Gearbox fault' and the amber warning light came on, meaning according to my guide book advisor. Red means take it to a dealer. I have also had a message flash up to do with the ABS. The original airbag warning was a lit symbol on the dashboard.

The solenoid and voltage codes were what the gearbox specialist found when they checked the gearbox. There was no code showing for the gearbox at all.

Hence, they say the gearbox is fine and the other garage say the codes are not matching any other problems, so in their experience it means an old code not cleared from the memory.

 

OK, now I think I see.

I've put the background way this (sort of) works in your other thread.

If you're getting what seem to be quite varied things, it's a bit worrying (but not necessarily time to panic). If they're pretty rare, I'd tend to have a good hunt around when you have a chance but otherwise wait and see. Sometimes there just doesn't seem to be a cause and they don't recur, but sadly other times you'll get a fault that keeps occurring.

If it's all apparently OK for now I'd just wait and see. Well.... if I had a heated garage and some spare time I'd be under the car, in it, and whatever, examining parts of the car with lights, mirrors etc - but I've not got the heated garage so can't say I'd be keen to freeze just on the vague hope of spotting a problem!

 

I got a new one yesterday, the park brake this time. Dealt with by switching off and back on again. They happen on start up and it seems to be dealt with by 'rebooting' the car by switching off and back on again.

 

Battery on its way out? (Or bad connections to it) Sure sounds like it.