Discussion
Can anyone help ?
I have a 2005 corsa 1.2, the head gasket blew so I renewed it along with the timing chain plus new plugs,filters and oil etc ,it now runs like a dream and has passed all the emission tests etc but won’t pass an MOT as the engine light is permanently on, I had it diagnosed at a local garage and they said it was the EGR valve, so I renewed that but no change !
I then had it diagnosed at a vauxhalll garage they said the same EGR valve or possibly oil in the loom,I removed the loom and checked it all plus cleaned all the plugs and sockets with contact cleaner , it all looks clean and dry and there was no signs of oil contamination, I have also tried another EGR valve as well, I bought a hand held OBD11 diagnose tool and deleted the code but it just keeps coming back, I have tried disconnecting the battery then re connecting and taken it on a long drive, as I say it runs like a dream but I will end up scrapping it if I can’t get it through an MOT,
Any ideas would be greatly appreciated.
I have a 2005 corsa 1.2, the head gasket blew so I renewed it along with the timing chain plus new plugs,filters and oil etc ,it now runs like a dream and has passed all the emission tests etc but won’t pass an MOT as the engine light is permanently on, I had it diagnosed at a local garage and they said it was the EGR valve, so I renewed that but no change !
I then had it diagnosed at a vauxhalll garage they said the same EGR valve or possibly oil in the loom,I removed the loom and checked it all plus cleaned all the plugs and sockets with contact cleaner , it all looks clean and dry and there was no signs of oil contamination, I have also tried another EGR valve as well, I bought a hand held OBD11 diagnose tool and deleted the code but it just keeps coming back, I have tried disconnecting the battery then re connecting and taken it on a long drive, as I say it runs like a dream but I will end up scrapping it if I can’t get it through an MOT,
Any ideas would be greatly appreciated.
I think you need to work out whether this is just the feedback voltage being slightly outside the spec, or a more fundamental fault.
Is the valve getting the 12V it needs to operate it? You could check with a couple of back probes and a volt meter. If it isn't, then replacing the valve is pointless.
If it is getting the expected voltage, is the EGR valve actually working? You should be able to test it off the vehicle just by sticking 12V across the connector. You could also check the voltage at the sense terminal to confirm it's giving the appropriate feedback. Finally you can measure the actual feedback voltage on the vehicle to see whether it's moving the same as on the bench.
Is the valve getting the 12V it needs to operate it? You could check with a couple of back probes and a volt meter. If it isn't, then replacing the valve is pointless.
If it is getting the expected voltage, is the EGR valve actually working? You should be able to test it off the vehicle just by sticking 12V across the connector. You could also check the voltage at the sense terminal to confirm it's giving the appropriate feedback. Finally you can measure the actual feedback voltage on the vehicle to see whether it's moving the same as on the bench.
I don't know whether it's driven directly by the ECU or via a relay. If you can track down a wiring diagram, that should tell you.
Either way, 5-6V doesn't sound right and suggests there is a problem on the electrical side. In my experience wires, relays and fuses typically fail in an all-or-nothing way and don't just give you a consistent big voltage drop - that sounds more like an electronic driver failure.
Either way, 5-6V doesn't sound right and suggests there is a problem on the electrical side. In my experience wires, relays and fuses typically fail in an all-or-nothing way and don't just give you a consistent big voltage drop - that sounds more like an electronic driver failure.
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