Just wanted to add some of my experience with these fault codes
Had a fault P0236
kept coming up. > over boosting.
1. P0236 Checked for fault > no vacuum at VNT actuator or solenoid/ fault fix was vacuum pipes had melted > replaced pipes.
Then another fault code reared its ugly head after the P0236 fix > P0235
2. Changed the MAP sensor, (had a new spare) only after cleaning my old one up as it was gunky, and things smoothed out a little better, but still got the P0235 code and reduced acceleration @2750rpm and upwards engine light comes on.
3. Removed the Turbo and stripped it down to find the usual problem of sticking vanes, after cleaning out the rust and carbon and reassembling/refitting the turbo unit this has fixed the P0235 fault code as the VNT are no longer stuck open causing over boost.
So after a little bit of work (
) its running perfect now and the power is smooth going through the gears revving over 3000rpm and no more engine light coming on and the inevitable limp mode
So if you have this type of fault
1. Check vacuum is present at the VNT actuator and associated parts are working (slam panel solenoid).
2. Map sensor is clean from gunge clean and or replace with new one if fault still present after step 3.
3. VNT has free movement disconnect actuator and free movement of the turbo vane arm should be 10mm at least.