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View Full Version : Help please to diagnose fault on VW Passat 1.9 Tdi 130.Saloon 53 plate South Shields area



xaghra
15-03-2009, 09:23 PM
I have an intermittent fault happens every 5-6 days. whilst car in motion ABS- EPS -Battery warning lights come on in that order, engines loses power and car stops.A VW dealerships had car for nearly two days and fault did not occur-It did not show up on diognostic equipment and visual check shows no corrosion on relays-bulb clusters no water seepage in to ECU managment system black box.
All electrical systems appear ok as does sensors. A DISS report was sent to VW HQ to their technical people but report came back that no one has come across this problem before.
Can anyone help please?

a8 tech
15-03-2009, 09:48 PM
So its cutting out without a fault code.First the abs and battery warning are coming on because the speed signal has been lost and battery warning is be caused the alternator voltage drop when the engine cuts out.I suspect also there is no warning like a misfire when this happens,this leads more into a brief voltage supply loss to the engine ecu

If there are no sporadic under voltage or open circuit fault codes stored in any of the control units then this fault can be isolated to defective supply relay or fuel supply
In this case i would replace the fuel supply pump in the tank and the engine ecu supply relay (this will not store a fault code) and also check the voltage at the earth side of the engine ecu

Running a dummy loom for voltage supply to the fuel pump relay and engine ecu would also worth considering to eliminate poor connection as well as replacing the engine ecu voltage supply relay as all these recommendations will not store a fault code if the vehicle restarts or briefly a sporadic fault will register in the drive train network.

kenney
15-03-2009, 10:36 PM
How do you get the engine started again,when the fault occurs?

xaghra
16-03-2009, 12:21 PM
turn ignition off for approx 2 minutes-turn ignition on again and car starts normally and is ok for 4-6 days then fault occurs again. Scary when it happens the middle lane