Computer glitch?
Discussion
Went out today and service warning came up. (VXR 6.0). Immediately the power dropped to tickover and then engine stopped altogether. Then the ignition went dead. There appeared to be nothing wrong with the oil pressure,water,temp etc. In fact, I'm pretty certain there was nothing wrong with the engine at all. I've had the service warnings come up before, and nothing wrong then either, but never the "safe mode" engine dissabling. Left the car for a while and it started ok. Any suggestions guys? Is there any way to put the computer's mind at ease?
Careful- any advice is pure speculation and bound to upset people 
However - safe mode is usually caused by something pretty well out of normal parameters.
how was the engine running before? Any misfires?
The most common fault I have had causing safe mode is when the crankshaft sensor doesn't pickup an acelleration when its expecting one. If this happens x time in y seconds then in order to stop large amounts of umburnt fuel getting to and dangerously overheating the catalytic converter it'll cut fuel to the affected cylinders and trip the service light. If it picks up too many misfire faults it goes into full on safe mode
The sensor is very sensitive and it can be that the driver soesnt notice an obvious misfire. worth checking the basics that plug leads are in ok and plugs are clean with no water in them. Normally the light will stay on for a few restarts and if the problem doesn't return within x starts it clears the light (but fault code log should still be there.
Problem is there are so many things that can trip the light. Most are electrical and often either misfires, a sensor failing (the only one I know that could trip safe mode is the crankshaft sensor) and the exhaust (the pre and post cat o2 sensors are quite fragile) however I have never knob an emissions code to go into safe mode.
If you can get an obd reader (I've got one if you are near Cambridge) then it will definately help diagnose the problem
However - safe mode is usually caused by something pretty well out of normal parameters.
how was the engine running before? Any misfires?
The most common fault I have had causing safe mode is when the crankshaft sensor doesn't pickup an acelleration when its expecting one. If this happens x time in y seconds then in order to stop large amounts of umburnt fuel getting to and dangerously overheating the catalytic converter it'll cut fuel to the affected cylinders and trip the service light. If it picks up too many misfire faults it goes into full on safe mode
The sensor is very sensitive and it can be that the driver soesnt notice an obvious misfire. worth checking the basics that plug leads are in ok and plugs are clean with no water in them. Normally the light will stay on for a few restarts and if the problem doesn't return within x starts it clears the light (but fault code log should still be there.
Problem is there are so many things that can trip the light. Most are electrical and often either misfires, a sensor failing (the only one I know that could trip safe mode is the crankshaft sensor) and the exhaust (the pre and post cat o2 sensors are quite fragile) however I have never knob an emissions code to go into safe mode.
If you can get an obd reader (I've got one if you are near Cambridge) then it will definately help diagnose the problem
Edited by ads_green on Sunday 1st June 08:35
Edited by ads_green on Sunday 1st June 08:38
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