17070 - ECM Power Relay Control Circuit (J271) P0686 - 35-00 - Short to GND in laymans terms? how do i fix it before carrying on with getting the car started?
info direct from the VCDS wiki http://wiki.ross-tech.com/wiki/index.php/17070/P0686/001670 it relates to the power supply for the Engine Control Module (J271 or J220)
from what i have seen this code pops up a lot on cars that have had an engine swap. more specifically the 1.8t engine into vehicles like the mk1,2 or 3. basically the ECU is searching for a control module that is probably no longer in use. as you don't want those features or need them such as airbags/abs/traction control etc etc
The J220 is in the black plastic box in the engine bay. You more than likely have got rid of it, I did. I also had that code but it didn't make a difference. I did get rid of it though, will look back through my notes. As you are able to vag-com the car the ECU is powering up anyway.
Hmm, might not be the same fault. Not sure what ECM is! http://www.clubgti.com/showthread.p...925-Power-Supply-Relay-for-ECU&highlight=J220
seems strange all the wiring diagrams i'm looking at on elsawin for the AUQ or AUM engines don't have reference to the J271 module?
after much fiddling about this is the info i have pulled from a 2001 onwards AUQ wiring diagram hope that helps you some what J271 - 2001 onwards Pin 1 & 3 = join together and trace back to positive feed in a long winded way trace back through T6m/4 (brown connector) to fuse S10 on relay plate Pin 2 = Connects to T2m/1 (2pin connector in engine compartment on left) which should trace back to the injector pin 1on all of those Pin 4 = Connect to T6m/1 (brown plug in plenum) and traces back to Fuse S229 on the fusebox
Had that code before on my AUQ loom and it was indeed the relay in the black box in the engine bay,they are numbered 100 and 428 I don't know which one it was that went as i replaced both.Problem solved I think as its not come back iirc.
hmm i don't have anything like that on my loom, everything sits on the fuse box, with relay 53 powering the ecu.
has the loom been modified to work in the mk1? if so it may have been removed during those modifications at a guess
ok i can't see that he'd have removed it tbh with you i have a bam loom unmodified so will grab a photo of that later on tonight and label the bit your looking for if you want as its a similar setup iirc
thanks, reading around this, its either something not to be worried about or it is something to be worried about. have jonny and see what he says. having killed one ecu i'd rather not do another.
To answer the question for everyone in here, this is indeed the ecu supply relay its crying about. but its not a problem, see what it is the ecu on the later mk4 can switch on its own supply relay, via an earth trigger! if you dont use the earth trigger wire and insted fit a normal switched live ecu relay then you get this fault code. it doesnt actually effect the runnign of the car from what I can see, but since I found out that the ecu will log this code i now utilise the ecu trigger wire and fit a different relay. to fix this, get a 109 ecu relay from a mk3 tdi/early vr6 and wire it in. it only has 3 pins, 1 is a permanent live input, then theres the output to the ecu, and the last pin is the earth trigger from the mk4 ecu. in a mk1/pre-90 mk2 you'll have to fit this relay above the fusebox in a (VW preferably) relay holder. in a 90spec mk2 or mk3 you fit the 109 relay into socket 3 and then run the ecu earth trigger to g1/7
