I had a problem of P0238 over boost error code on my 2006 1.9 JTD Doblo diesel.
Let me share the process of diagnosis in case it helps someone.
First I removed the MAP sensor and saw it was caked with dirt and impossible to clean. I replaced it. Easy job as just one screw and a connector to remove. The car ran better but still low power especially going up hills.
Then I suspected a problem of stuck actuator rod on the waste gate of the Turbo. To check this I took off the bottom panel of the car and shone a light up on the actuator arm as my son revved the engine. No motion at all even after spraying some wd40 on the actuator arm. Then I removed the vaccum pipe to the waste gate actuator and discovered with my finger that there was no vaccum. I suspected a hole in the vaccum hose.
Finding the hole was not easy as the access to the vaccum hose is poor over a lot of its length and it feeds behind the engine where there is very little room. I unscrewed the mounting bracket of the fuel filter and pushed it to one side. I removed the pipe from the Exhaust Gas Recycling valve to the engine and cleaned it. Reaching below through the free space I was able to seize the vaccum hose and found the hole which I fixed temporarily with electricans tape. After putting back the EGR pipe I started the engine and this time the actuator arm moved and came back each time I took the vaccum pipe on and off it’s nipple on the actuator body.
Upon doing a test drive I found full power was restored and the car could drive up hills at speed with plenty of power.
Now I just need to buy a new vaccum hose and fit it next time I am working on the car…
Let me share the process of diagnosis in case it helps someone.
First I removed the MAP sensor and saw it was caked with dirt and impossible to clean. I replaced it. Easy job as just one screw and a connector to remove. The car ran better but still low power especially going up hills.
Then I suspected a problem of stuck actuator rod on the waste gate of the Turbo. To check this I took off the bottom panel of the car and shone a light up on the actuator arm as my son revved the engine. No motion at all even after spraying some wd40 on the actuator arm. Then I removed the vaccum pipe to the waste gate actuator and discovered with my finger that there was no vaccum. I suspected a hole in the vaccum hose.
Finding the hole was not easy as the access to the vaccum hose is poor over a lot of its length and it feeds behind the engine where there is very little room. I unscrewed the mounting bracket of the fuel filter and pushed it to one side. I removed the pipe from the Exhaust Gas Recycling valve to the engine and cleaned it. Reaching below through the free space I was able to seize the vaccum hose and found the hole which I fixed temporarily with electricans tape. After putting back the EGR pipe I started the engine and this time the actuator arm moved and came back each time I took the vaccum pipe on and off it’s nipple on the actuator body.
Upon doing a test drive I found full power was restored and the car could drive up hills at speed with plenty of power.
Now I just need to buy a new vaccum hose and fit it next time I am working on the car…
