I have a 04 plate Vauxhall Vectra Estate 1.9cdti which has a recurrent problem. The warning symbol - car with spanner through keeps coming on and will only go off if I stop the car & restart, but will then come on again after about 15mins or even weeks, when this happens the revs drop to tick over. Also recently the control indicator for exhaust (looks like engine) has come on and stays on even when engine switched off and restarted. Have already taken it to dealer and was hooked up to diagnostic machine but no codes showed up. Any ideas what could be causing it??

Bob Holmes, November 2009

can the trottle valve be repaired has i noted it has screws to take it apart

mark bedford, November 2009

Did the dealer use the proper Vauxhall "Tech 2" Diagnostics?
Vauxhall diesels often wont communicate with generic code readers. I'm assuming it's a proper Vx dealer.
A common fault with these is the Mass Air Flow (MAF) sensor. This can also cause emmision faults as it gives the engine computer wrong info on airflow. A good quality replacement MAF is quite expensive to buy, but a simple DIY fit. Copy and paste link-

http://www.autovaux.co.uk/LoadPortal.aspx?cnum=11&pnum=AS93178243&tabid=5&vnum=137

Dont bother with cheap ones off auction sites, they are cheap for a reason.
You could try borrowing one from a known good car.
I wouldn't spend money on parts until getting the diagnostics done by someone competent.
There are so many systems and sub systems which can cause problems replacing parts at random will bankrupt you.

A half-decent tech 2 operator should be able to scope the MAF and other sensors and actuators using the live-data function, a GOOD operator will be able to spot any anomalies in the various outputs.

gus, November 2009

Buy a cheap code reader off Ebay and read the code yourself

They are only around £20

Mike, November 2009