Sedici 1.9 diesel 4x4 getting MIL and codes P0111 Intake air temp sensor 1 circuit range/performance & P0235 Turbo boost sensor A circuit.
Have replaced the MAP but still get codes. I can reset and start the car and the MIL stays off but stopping and restarting puts it back on again and same codes.
Found a split in turbo wastegate vacuum pipe, fixed but still same codes, cant actually see if the wastegate is moving or get my hand on to see if it is seized. Would a seized wastegate give these codes? seems like a dockyard job to get it off. The car drives fine but need to get the MIL off.
Could it be the ECU? Would check the wiring from MAP to ECU but there are 4 wires and all the wiring diagrams i have seen are 3 wire so stuck on that one.
Any further suggestions gratefully recieved :bang:

Check VTG (tennis ball sized unit under turbo w/rod sticking out of the top) - if the car has been driven with a split vac hose to the actuator for some time there´s a good chance the mechanism has seized.
Having a combination of MAF/MAP errors caused by something completely different is not too uncommon with these engines. Ours also started throwing random MAF, EGT and other errors when the DPF was blocked. Unless the sensors or their wiring are completely shot (unlikely), MAF and MAP sensor errors simply mean that the engine is unable to bring air mass and air pressure into the desired ranges by using its actuators...

Thanks niggles, I do suspect the wastegate being stuck, as on top of the vacuum pipe split the car has been parked up for 6 months and only ran at idle on the drive every now and again. The MIL light was on before it was parked up. Also now if not started every day it becomes difficult to start.
I know the turbo is part of the exhaust manifold but assume i can still strip it down once its off the car? Looks like a bit of a dockyard job but really think it needs to come off.

There is no waste gate on a VNT turbo. The VNT actuator rod turns a ring inside the "hot" turbo housing that directly regulates the amount of boost. This ring is not lubricated and needs to be exercised through its full travel regularly to stop it from sticking due to carbon deposits. You don´t need to start pulling things apart just yet. Use a mechanic´s mirror and a small torch to check if the rod is traveling up and down smoothly while the engine is being revved. There is also a special tool (long stick with handle and a small spanner head welded on at an angle) that lets you engage the rod and exercise it manually. Don´t use too much force though, you might damage the actuator´s membrane.
Your starting problems are completely unrelated. Use a heavy jumper cable (35sqmm min.) to connect the negative terminal of the battery directly to a clean spot on the engine block. If this improves starting it´s high time to replace the rotten main ground wire. While you´re at it also replace the flimsy battery terminals with beefy aftermarket ones and stick the biggest battery in there that fits the holder. A 72Ah one works well.
The reason for that is the design of the hp fuel pump. As it ages and wears it needs higher starting revs to achieve the 300 bar minimum pressure that prompts the EDC to commence injection. Conversely the aging starter and deteriorating (badly designed...) ground wiring progressively lower the starting power. So at some point you need to beef up the electrics to get things in line again.

Story update - couldnt see the actuactor arm moving so bit the bullet and dismantled the car to get the turbo off (usual complete nightmare job) the arm was moving but a bit tight and sticking a bit mid travel so stripped the turbo and cleaned the ring, actuator arm now easier to move. refitted and noted another split vacuum pipe so sorted that. Started and found the turbo to spin up nicely , cleared the codes and had a test drive all good. stopped half way round and switched off the engine and restarted to be greeted by the MIL light again. back home i again cleared the codes but each subsequent startup the light is back on. Also now getting code P0069 Baro pressure.
Losing the will to live with this car now.

IAEGMOOH said:

Story update - couldnt see the actuactor arm moving so bit the bullet and dismantled the car to get the turbo off (usual complete nightmare job) the arm was moving but a bit tight and sticking a bit mid travel so stripped the turbo and cleaned the ring, actuator arm now easier to move. refitted and noted another split vacuum pipe so sorted that. Started and found the turbo to spin up nicely , cleared the codes and had a test drive all good. stopped half way round and switched off the engine and restarted to be greeted by the MIL light again. back home i again cleared the codes but each subsequent startup the light is back on. Also now getting code P0069 Baro pressure.
Losing the will to live with this car now.

Click to expand...

P0069 is directly related to the MAP sensor. Take the car for a short spin while graphing desired boost pressure vs. actual boost pressure. You probably still lose boost pressure somewhere - might be split hoses, a leaking intercooler or something as simple as having forgotten to tighten up a hose clamp after refitting the turbo.