Evening All,

Mrs Stevesteve reported that the engine warning light has come on on the Multipla.

I dug out the ECU-USB cable and installed Multiecuscan on this laptop as I had scrapped my old IBM that I used to use. COM6 worked once I read the manual and set the Latency Timer down to '1'.

The error showed as P0235. However when I cleared the error Several times I noticed two differet messages had been displayed:
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* P0235 - Boost pressure sensor

Boost control solenoid or boost pressure sensor faulty. The reason for this fault is that ECU has received invalid signal from the sensor. The fault is present now. Take appropriate action to fix this sensor fault. Dashboard warning light was activated for this fault.​

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* P0325 - Supercharging pressure

Boost Pressure sensor A circuit malfunction
The reason for this fault is that ECU has received invalid signal from the sensor. The fault is not detected now but is stored in memory. Clear Fault codes and observe for future appearance of the same fault.Dashboard warning light was activated for this fault.​

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So my questions are:
1. What is the most likely cause of this?
2. What needs to be fixed and does anyone have any clear diagrams of where is is in the engine bay?
3. How serious is this?
4. Can the car be driven in this state?

Cheers,
Steve

1. What is the most likely cause of this?
A seized-up boost control solenoid valve, a MAP sensor gone duff, or a split in the small diameter vacuum pipe(s) that connects everything together.
2. What needs to be fixed and does anyone have any clear diagrams of where is is in the engine bay?
A new boost control solenoid valve (don't bother trying to fix the old one) - about £40-75 depending on where you buy it from and whether you get lucky with a dealer having a clearout on ebay. Pierburg ones are good. It's located right next to the battery shelf, near the engine and has two small rubber pipes of about 8-10mm diameter pushed on to its bottom end.
OR
Try cleaning the gunk out of the inside of the MAP sensor with some brake cleaner spray and cotton buds. If that doesn't work, a new one is £50-60. It's fitted to the back of the cylinder head by a single bolt, usually allen key or torx head.
OR
check the condition of the run of small diameter rubber pipes, in particular there's one that runs from the turbo actuator to the boost solenoid valve (it's usually, but not always, red) that's know to split. Look for it directly behind the radiator. Examine the ends of all of the pipes carefully for perishing. Even a small split of a few mm will allow atmospheric air to get in, stopping the vacuum actuation. Replacement pipe is about £5, so check for this fault first.
3. How serious is this?
Not very. It just makes the car a pain to drive.
4. Can the car be driven in this state?
Yes. All it means is that the variable geometry on the turbocharger won't work, so it will feel a bit flat. If the ECU puts the car into Limp Mode to protect the engine, it will feel very flat. Have the fault reset, then take the car out, get it into fourth at about 1500rpm-ish on a straight, clear piece of road, then floor it for as long as your nerve holds. If you get to 3,000rpm, it beeps and the engine management light comes back on, you're loosing vacuum pressure in the actuator circuit - the cure will almost certainly amongst of the above list.

My vote is for the EGR Valve - buy a new one. 1 hour to fit.
Regards
Stephen

Definitely not an hour to fit an egr on a jtd..
Its a right pain in the arse to undo..much better just to blank it

Ok. How about fitting a blanking plate, resetting the ECU and then checking again?

If the EGR Is the problem should that stop the error code? - I am thinking of a diagnostic route.

With the option of them swapping out the EGR in due course.
Cheers
Steve

I do not understand why everyone has a problem replacing the EGR. I can do them in in an hour. OK if you have never done it before and have to faff then it would take a bit longer.
Regards

Hi Widemouthfrog,

Thanks for your detailed reply I will check each of the cheaper parts that you recommended before starting on anything expensive!
Cheers
Steve