Astra H 1.7 CDTI 2007
Z17DTH engine, EDC16, Bosch No. 0 281 012 694, ECU under n/s wheel arch.

Fault code P2279-11 air leak in inlet manifold

Vehicle good starter, runs well no problems, as long as you drive steady.

Accelerate vehicle hard no problem until you back off throttle, fault code is set after 5 to 7 seconds, vehicle goes into limp home mode, this occurs each and every time.

Pressure tested intercooler to 15 lb pressure no leaks, smoke tested inlet manifold etc.

Removed swirl flaps, checked them, all ok.

Checked valve timing all ok.

Parts fitted by PREVIOUS garages, reconditioned turbo then new turbo, new EGR valve, I have tried blanking off new EGR no difference.

Tested map sensor, ignition on, engine not running / engine running.
If you remove sensor and apply steady pressure with a pump to sensor, the voltage rises smoothly up to about 4.25 volts measured on live data and on oscilloscope.

Reading live data, once map sensor VOLTAGE reaches about 2.3 volts the engine ECUs interpretation of pressure goes all to pot, flying straight up to 3bar.
If you remove pressure from sensor, PRESSURE reading in live data hangs at 3bar for 5 to 7 seconds then crashes to zero.

Voltage shown on diagnostics dose not hang but drops to zero when pressure released.

If you simulate a voltage from sensor to ECU, any voltage below 1.7 volts causes ECU to read 3bar and any voltage above 2.3bar dose the same, in between these all ok.

Have tried a new sensor, rewired sensor back to ECU, same condition, checked 5 volt feed, earths, etc. all ok. ECU main supply and earths all ok.

Fitted a replacement ECU, had ECU reflashed latest software, no change.

Have tested Map sensor on several other Vauxhalls but not the exact same model, no other vehicle behaves like this, all others, as voltage rises pressure indicated on diagnostic tool rises and dose not hang.

My thoughts are still a faulty ECU, would like try ECU in another vehicle but cannot find same vehicle, Have run out of ideas, has anyone got any.

If anyone has same model would you be prepared to test this ECU in their vehicle. No ECU testing firm will check this ECU.


Malc Morley