I thought id try this as a last resort... we are a dealership and we have a VW Fox 1.4 2006 (56) BKR engine which keeps randomly throwing an EPC light and going into limp mode (virually undrivable at snails pace). Turn ignition off and on again, resets, all drives ok till the next time. Sometimes its days before it comes back, then it can happen every minute multiple times a day. Totally random. We have also had the EML come on occasionally, then it tends not to reset on the ignition and the codes have to be erased to get it to run again.
Originally it had the following codes in the ECM when it first came into stock with us:
17070 - P0686 ECM Power Relay Control Circuit - J271 Short to ground - Intermittent
17951 - P1543 Angle Sensor Throttle Motor - G187 Signal Too Low - Intermittent
17580 - P1172 Angle Sensor 2 Throttle Motor - G188 Signal Too Low - Intermittent
We have since cleared the codes, and every time it does it, its just the P0686 ECM Power Relay Code that comes back. Throttle angle sensor codes have never been back since the first day we scanned it.
As such all efforts have been spent on the J271 relay. Its been replaced to eliminate a faulty relay. Someone else suggested changing the ignition switch so we did that. Thought we had fixed it as it drove fine 3 days, then it came back again. Battery has also been replaced.
Im now wondering if the original P1543 and P1172 codes are the source of the problem even though they dont come back when the car goes into limp mode and EPC comes on. Is there a chance a wiring fault on the throttle body could be intermittently cutting the feed to the J271 relay, hence why we keep getting that code come back and not the throttle motor codes? Whats the chances of both sensors being intermittent... or could 1 cause the other to come on? Is there any known wiring harness issues?
I also read on another forum that on some models, the O2 sensors are wired into the throttle motor and ECM and problems on that can mess with voltages to the ECM flagging Throttle codes? To be honest we are just not sure where to look next.
Any ideas, or advice appreciated. Its so frustrating as you never know when its fixed as its so random, but im hoping some pros out there may have come across similar symptoms before.
Adam: This forum is centered around US market Foxes manufactured between 1987 and 1993. Our cars don't generate/store fault codes at all (except for 1990-91 CA cars) so we don't deal with any issues similar to the one you've described. I'm guessing there must be a forum specific to late model Foxes somewhere.
I have a fox now with the exact same problem.
Did any of you find the solition. I have tried new relayes and checked connections.
I really hope you guys got it right since the tread startet
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