P0235 fault code
This code appeared via multiecuscan, on a Doblo 2005 multijet.
I noticed that the voltage readings were very stagnant whatever rpms were applied.
Constantly at 1.75volts.
Possible causes were wiring and the MAP sensor itself. I checked the wiring with a
multimeter, but found all results were well within there parameters.
So concluded it must be the MAP sensor. Bought a new one at Agnelli's for 100
euros. Put it on...............no difference.
Started to think that the sensor was ok all along. Stared to think about other causes.
Maybe the wastegate on the turbo was not opening as it should. Slapped the car on
the lift, with a torch, had a look to see if there was any movement under
acceleration. Dead as a door nail. Tried moving it with the aid of a screw driver.
No luck. I removed the rubber pipe which connects the turbo air side (compressor)
to the boost pressure solenoid, which is respnsible for moving the wastegate.
I connected up an air line and applied afew shots of air. Hay presto....it moved.
I then wanted to see if any air was coming out of the pipe on the turbo.
I started up the car, and checked for air coming out under differing rpm ranges,
NO AIR at all. Maybe the pipe was blocked. So I checked, and found it was
blocked solid. I cleaned with alittle WD 40 and a metal coat hanger with a sharp
point, and eventually freed it clean.Started to think that the turbo wasn't revolving.
Next I removed
the 2" approx. rubber pipe which supplies the compressor with air. Once removed
with my favourite torch I could see the compressor wheel/impeller. Once again,
I started up the engine, too see if the wheel would spin...No spin at all.
So I got a 8mm socket on the end of the wheel shaft, and found it was sticking
in certain locations. So I applied some WD 40 on the compressor wheel face
and gently started to spin the wheel with the 8mm socket, until finally it spun free
as a bird. Still with the rubber hose removed, I started the engine, and to my suprise
the compressor whell spun with it usual whistle sound, (thats the best description I
can give it).
Delighted with my first bit of progress, I wanted to see if the air would come out of
pipe which connects to the boost pressure solenoid via the rubber hose.
You know whats next..............STARTED THE ENGINE....with afew stabs of the
pedal, air finally came out of the pipe. Magic. Now lets see with the hose connected
back on, would it operate the solenoid and then the wastegate with higher rpms.
It did, not very much mind, but opened all the same.
Before putting back the 2" rubber hose onto the turbo, I just checked it inside.
Was alittle surprised to find oily gunk collected at the bottom of the rubber hose.
Cleaned it all out, and reconnected back up again.
All that was left was to drop it off the lift...............and drive it as if I stole it!!!
Hit the road and went like a rocket!!!
I'll finish here, but Ill put up another thread called P0235 part 2, just to say what
I think was the sequence of advents.
John.
This code appeared via multiecuscan, on a Doblo 2005 multijet.
I noticed that the voltage readings were very stagnant whatever rpms were applied.
Constantly at 1.75volts.
Possible causes were wiring and the MAP sensor itself. I checked the wiring with a
multimeter, but found all results were well within there parameters.
So concluded it must be the MAP sensor. Bought a new one at Agnelli's for 100
euros. Put it on...............no difference.
Started to think that the sensor was ok all along. Stared to think about other causes.
Maybe the wastegate on the turbo was not opening as it should. Slapped the car on
the lift, with a torch, had a look to see if there was any movement under
acceleration. Dead as a door nail. Tried moving it with the aid of a screw driver.
No luck. I removed the rubber pipe which connects the turbo air side (compressor)
to the boost pressure solenoid, which is respnsible for moving the wastegate.
I connected up an air line and applied afew shots of air. Hay presto....it moved.
I then wanted to see if any air was coming out of the pipe on the turbo.
I started up the car, and checked for air coming out under differing rpm ranges,
NO AIR at all. Maybe the pipe was blocked. So I checked, and found it was
blocked solid. I cleaned with alittle WD 40 and a metal coat hanger with a sharp
point, and eventually freed it clean.Started to think that the turbo wasn't revolving.
Next I removed
the 2" approx. rubber pipe which supplies the compressor with air. Once removed
with my favourite torch I could see the compressor wheel/impeller. Once again,
I started up the engine, too see if the wheel would spin...No spin at all.
So I got a 8mm socket on the end of the wheel shaft, and found it was sticking
in certain locations. So I applied some WD 40 on the compressor wheel face
and gently started to spin the wheel with the 8mm socket, until finally it spun free
as a bird. Still with the rubber hose removed, I started the engine, and to my suprise
the compressor whell spun with it usual whistle sound, (thats the best description I
can give it).
Delighted with my first bit of progress, I wanted to see if the air would come out of
pipe which connects to the boost pressure solenoid via the rubber hose.
You know whats next..............STARTED THE ENGINE....with afew stabs of the
pedal, air finally came out of the pipe. Magic. Now lets see with the hose connected
back on, would it operate the solenoid and then the wastegate with higher rpms.
It did, not very much mind, but opened all the same.
Before putting back the 2" rubber hose onto the turbo, I just checked it inside.
Was alittle surprised to find oily gunk collected at the bottom of the rubber hose.
Cleaned it all out, and reconnected back up again.
All that was left was to drop it off the lift...............and drive it as if I stole it!!!
Hit the road and went like a rocket!!!
I'll finish here, but Ill put up another thread called P0235 part 2, just to say what
I think was the sequence of advents.
John.
