Opel Vectra 2001 1.6 ECU Faulty

[leonard]

After about 1 hour driving the the car stalls
When i start the engine, i found that the control line from the ecu to the fuel pump relay
is around 300mV then starts to rise slowly over 30-40 minutes, then goes up to 12v shutting down the fuel pump
I shorted this control line to chassis, and the engine will run ok.
all powers and grounds are ok,
The Ign 12v is ok.
I suspect the ecu to be faulty,
Does anyone know what the procedure is to change the ecu.

Topic

[college man]

sounds like ground issue or the line opens. If you ground
something that is getting 12v you would have a short. It
should not run as described.

[leonard]

If there is 12v at one side of the relay control, it goes thru the coil of the relay and appears as 12v on the ground side, until the driver in the ecu switches the ground end of the relay to ground (0V) this creates a magnetic field in the coil and the contacts in the relay closes
but the driver in the ecu has a thermal problem
I have the ecu apart, when the driver is faulty, I spray freezer on the ecu pcb, this clears the fault
shorting the ground end of the relay is only doing the job of the ecu

[college man]

[quote=”leonard” post=80038]If there is 12v at one side of the relay control, it goes thru the coil of the relay and appears as 12v on the ground side, until the driver in the ecu switches the ground end of the relay to ground (0V) this creates a magnetic field in the coil and the contacts in the relay closes
but the driver in the ecu has a thermal problem
I have the ecu apart, when the driver is faulty, I spray freezer on the ecu pcb, this clears the fault
shorting the ground end of the relay is only doing the job of the ecu[/quote]

I see. do you have another ecu?

[Kevin Criswell]

I dont have access tot he wiring diagrams for an Opel, but I would start with this.

Pull the fuel pump relay, take a voltmeter and place the positive probe on the control terminal coming form the ECM and take the negative lead and place it on the battery ground terminal. Turn the key on and check the meter you should have less than 100 millivolts of drop. This will help determine if the Control wire has unwanted resistance causing you fuel pump relay to kick off and stall the engine.

Next place you positive probe on pin 4 of the obd II connector. Diagram linked below. And the negative to battery negative (you might need a jumper wire) and turn the key on this pin in the ECM’s ground reference signal and this test will test the ECM’s ground voltage drop. Once again the meter should read 100 miliviots or less.

https://www.dropbox.com/s/c0m8zdiizslyudc/OBD-II_Pinout.jpg

[leonard]

Thanks for your reply, I have already done this test and all the grounds and supplies are correct ie under 100mV and 12V at the supplies
but the driver switched ground is the only one that is changing
I must post the scope capture of it changing

here is picture of moment of shut down, as you can see the coils are still firing

[leonard]

I can get one, but I need to know the procedure to programming it,ie do I send it to the main dealer ship

[college man]

[quote=”leonard” post=80165]I can get one, but I need to know the procedure to programming it,ie do I send it to the main dealer ship[/quote]

I would try contacting the dealer to see what the procedure would be.

[Kevin Criswell]

[quote=”leonard” post=80165]I can get one, but I need to know the procedure to programming it,ie do I send it to the main dealer ship[/quote]

Not sure, no Opel dealers on this side of the pond. I can tell you with our domestic brands, modules all have to be flashed to match the vehicle they are going on and very few shops (at least here) have the pass-through to do it.

[leonard]

Thanks for your reply
I have recently returned to auto Electrics after about 18 years from it, but I have being working as an electronics tech sense. The electronics on a auto don’t give me a problem, but the software end is hard to get any info on
I might have to bring it in to a Opel Dealer in the end (I hate to lose work)
it would also be nice to know how to program these ECU modules IE What Software is best and what type of interface to use
I know we have EOBD and the USA have OBD2,
but for the most part they are the same
not too sure about the security systems and other modules
but again, thanks

[college man]

Keep us posted on your progress.

[Author]

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