What year is the car and do you know the engine code, eg X20XEV.
When the cars computer detects a fault the light comes on and the engine goes in to "limp home" mode. This restricts the revs and alters the ignition and fuelling to protect the engine.
It will also store a fault code in the cars memory, which can be read using the appropriate diagnostic equipment. Most independent garages can do this for about £25/£30, dealers will be much more expensive.
Depending on the year of the car you may be able to read the codes DIY.
Tell us what year car is, or get it read and start a new post.
Be aware that just because a fault code refers to a certain sensor it is not necessarily that sensor which is faulty. For instance, the code may refer to the lambda sensor, but the fault could be caused by a leaking exhaust or faulty air flow meter.
A cam sensor code could be caused by a failing timing belt tensioner or roller.
Use the code as a guide, not an instruction to replace that part.
digger, September 2009
