Hi All After my 16v 1.9 cdti dropped into limp mode giving a code of 0243 I looked around for a fix. The code shows as a wastegate solenoid or boost pressure depending on the list you look at. Dived straight in and bought a second hand solenoid (Vacum sensor) and fitted it, a simple job. Didnt work for course. Took the car to a large diesel specialist who diagnosed the boost valve faulty, quoted £680 plus vat for parts plus unknown labour at £60 per hour. Off to the main dealer whose diagnostics man confirmed the fault as the boost valve ( exhaust manifold, turbo and boost valve all one part). Managed to get the above advise for free. Still finding it hard to believe all this I took the car to a guy in a tatty yard who repars trucks but with a good reputation for not ripping people off. Left the car with him. He rang me a day later to say a guy with was calling the next day with vauxhall tech gear and would check the astra while he was there. His opinion was the solenoid that I had changed was still faulty saying put a new genuine one on. Off I went bought a new one shot back and fitted it myself, once again no change. The truck fitter said it had to be a wiring fault associated with the solenoid and started pealing back the wiring loom. Sure enough about 8 inches from the solenoid he found that it had rubbed against the engine and worn through a wire. 10 minutes later, everything working, full power at last.
He then explained how to test the turbo and boost valve.
At the wastegate solenoid ( vacum sensor ) remove the two vacum pipes, connect them together so sending the vacum around in a loop to the boost valve. Start the engine and feel the air pipe from the turbo to the intercooler, if its rock hard the the turbo is working and the boost valve has operated. If its soft and you can squeeze it the the fault may well be with the turbo and valve. You must check that the vacum pipes are not leaking.
WARNING its not recommended to run the car like this as it will be on maximum boost.
This may work for other engines?
You can also check the vacum by pulling the rubber pipe off the vacum pump and sticking your finger over the end of it, if it sucks on your finger its working, follow the pipes to the solenoid. ( Dont pull the brake vacum pipe off its the bigger one ).
The horror would have been to pay for the manifold to be changed then what, an ECU, then what... it could have been horrendous, as it was it cost me £100 for the time spent on it plus a couple of sensors I didnt need but you have to start some where.
A long tale with a happy ending.