Having just had my 80k mj serviced mot done and error code p0106 cured by replacing Maf sensor I believe. Lo & behold a few hundred miles more I am presented with P0235 any help welcome symptom no power flat response above 2500-2800 boost ok no clouds of smoke turbo whistles away merrily up to this point.
I was wondering could the garage have trapped or kiked a pipe?
Any experience of this or ideas please.

joe1962 said:

Having just had my 80k mj serviced mot done and error code p0106 cured by replacing Maf sensor I believe. Lo & behold a few hundred miles more I am presented with P0235 any help welcome symptom no power flat response above 2500-2800 boost ok no clouds of smoke turbo whistles away merrily up to this point.
I was wondering could the garage have trapped or kiked a pipe?
Any experience of this or ideas please.

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According to the look-up table that came with my code reader:
P0235 : Turbocharger Boost Sensor - Circuit malfunction

Looks like you have a different problem now
It might be something easy though - check any/every connector you can see

I think you will find there is not a problem with the sensor or its wiring in fact the sensor is telling the truth that there is too much pressure in the inlet manifold when the revs go high which then makes the ecu put the engine in limp home mode i.e. not much power above 2500 revs ... If you look behind the turbo from underneath you will see the actuator if you pull the rubber pipe off the manifold and connect to an air bed pump or air line when the pressure gets to around 20 psi the rod should start to move I think you will find yours wont

Nothing to do with Fiat, but in the early 40's I went to primary school in Trimdon. Bet it's not there now. Lived in Coxhoe at the time. Back to Fiat, what code reader do you have?

tipouno said:

Nothing to do with Fiat, but in the early 40's I went to primary school in Trimdon. Bet it's not there now. Lived in Coxhoe at the time. Back to Fiat, what code reader do you have?

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Trimdon's still here.... most of it much the same, some old bits gone and with a few new bits added on! http://trimdon.com (my website)
I've got an RAC (aka Hilka) code reader, bought after many early problems with our MJ, thankfully sorted now.

Got the bezzler sorted turns out the new sensor had failed shortly after fitment grounding out to earth causing the code fixed free of charge usual good service by Walkers South Otterigton. If anyones looking the loan car was a black 1.2 dynamic also for sale very good drive low mileage £4.5k.

joe1962 said:

Got the bezzler sorted turns out the new sensor had failed shortly after fitment grounding out to earth causing the code fixed free of charge usual good service by Walkers South Otterigton. If anyones looking the loan car was a black 1.2 dynamic also for sale very good drive low mileage £4.5k.

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Just wondered if you could give me some more information on how they fixed it.
Mine was showing the same code, I removed the sensor to find it totally caked with carbon. I replaced it with a new Bosch one but the message keeps coming back and also with engine failure message, and then limp mode but then clears itself.

jetjem said:

Just wondered if you could give me some more information on how they fixed it.
Mine was showing the same code, I removed the sensor to find it totally caked with carbon. I replaced it with a new Bosch one but the message keeps coming back and also with engine failure message, and then limp mode but then clears itself.

Click to expand...

I think you will find there is not a problem with the sensor or its wiring in fact the sensor is telling the truth that there is too much pressure in the inlet manifold when the revs go high which then makes the ecu put the engine in limp home mode i.e. not much power above 2500 revs ... If you look behind the turbo from underneath you will see the actuator if you pull the rubber pipe off the manifold and connect to an air bed pump or air line when the pressure gets to around 20 psi the rod should start to move I think you will find yours wont

does this not apply..??, :idea:
Charlie

It could be, as already suggested the wastegate/vane actuation of a VGT, though I think it's a wastegate on these.

I'm unfamiliar with this models exact turbo set up, but I presume the wastegate/vane is actuated via an arm into the turbo which is operated via a vacuum or electronic box.

If it's visable, it should be wastegate open (arm at one end of it's travel) with the engine off.

Start the engine (idle) and it should move to the other end of it's travel and wastegate is closed.

Increase RPM slowly towards the red line and it should move back towards wastegate open, this is how it limits boost as rpm/exhaust pressures rise. (if it doesn't, it's likely to detect overboost and trip limp, hence why it often trips when acelerating)

If it's not performing like that, either there's a vacuum leak on the pipe, a leak in the diaphram of the actuator, (or electronic box is knackered) or more likely the wastegate in the turbo is coked up and stuck.

This last one can be checked fairly easily, if follow the actuator arm to the clip and remove it, the arm into the turbo is free to move back and forth.
Work it like this, if it's stiff, it's coked up and a bit more working is needed to get you by (until it cokes up again) or you clean the turbo out.

There have also been a few duff reading from MAP sensors reported, these read the air pressure in the air intake after the turbo.
A faulty reading should be easily spotted if you have a diagnostic tool to read it's output and could over read and tell the ECU there's more air under pressure than there actually is, though the coked up wastegate/actuator is more likely.