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Kevin, Master tech
Category: Vauxhall
Satisfied Customers: 1952
Experience:  Diagnostic technician
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I have just bought a 2005 corsa 1.0 twinport as a non runner

Customer Question

I have just bought a 2005 corsa 1.0 twinport as a non runner there was no eml showing at all so I checked the live and the switched live to the ecu as well as the earth which were fine I then fitted a second hand ecu kit on removing the ecu I noticed that the old one had writing on saying reset tech 2 so I belive this was also a replacement at some point ... I put the second hand kit on and it ran beautifully but I came to it today and it is now intermittently not starting when it doesn't start the eml and the spanner light flash one after the other I have checked the conector to the instruments and it is fine when the lights are flashing there is a clicking sound from the throttle body .. I have plugged it in and in body control I get the fault code no communication with ecm not present I clear it and try again and it comes back the same I have no faults in the immobiliser and non in the engine I can't seem to communicate with the instruments but I had that problem before when it was running I am now at a loss
Submitted: 1 year ago.
Category: Vauxhall
Expert:  Kevin replied 1 year ago.

Hi I'm Kevin the ecu you fitted are you 100% on the quality this is a very common fault with the engine ecu failing bringing the can us network down causing the comms fault intermittantly normally, the only way to really test is to scope the can signals from the engine ecu

Customer: replied 1 year ago.
The car it came off was running very well and when the engine starts it runs really well I can't see it being the ecu I can communicate with it and have no problems have u seen the alternate flashing of the eml and spanner light before ?
Expert:  Kevin replied 1 year ago.

To be totally honest no normally just spanner but u have a comms break down which is causing the non start try playing with the plug on engine ecu

Customer: replied 1 year ago.
I have tried all the quick fixes and I can't replicate the problem when it runs I wiggle everything behind the instruments and in the engine bay switch it off start again and it starts don't do anything and it doesn't start. I have read something about a white wire being corroded somewhere which causes can communications problems but I'm unsure where
Expert:  Kevin replied 1 year ago.

If you follow loom from engine ecu it normally gets water ingress into wires around the abs pump area

Customer: replied 1 year ago.
Would that be the engine loom side or the car side?
Expert:  Kevin replied 1 year ago.

Engine loom

Customer: replied 1 year ago.
Ok ill give that a look tomorrow and then if that is the problem I'll rate and credit cheers
Expert:  Kevin replied 1 year ago.

Let me know how you get on

Customer: replied 1 year ago.
Morning I haven't changed the loom yet but I have had another look .. when the lights on the dash are flashing it is at the same time as the throttle body is clicking I have plugged it in again and on live data the fuel relay is not active I have swapped both purple relays around which made no difference . If I unplug the throttle body the clicking stops and lights stop flashing I have reset the ecu and body control re programmed and no difference
Expert:  Kevin replied 1 year ago.

This makes me think even more that you have an ecu fault

Customer: replied 1 year ago.
If that is the case which I really hope it is not could there be something damaging the ecu as this car has now had 3 different ecu on it
Expert:  Kevin replied 1 year ago.

I would check the wiring before going any further

Customer: replied 1 year ago.
I have just unplugged the throttle body and the engine starts every time obviously without acceleration but runs perfectly other wise ? Surely not the ecu ?
Expert:  Kevin replied 1 year ago.

Check the wiring it is unlikely that the throttle body itself would cause this type of fault more likely bad circuit