ECM power relay

[pimp'n]

Changed my spark plugs today... five minute job turned into a nightmare! tried to start the car (1.8t 2003) after and it wouldn't start. checked with VAG-COM and got the following error message Faults Found:17072 - ECM Power Relay Load Circuit: (J271): Open P0688 - 004 - No Signal/Communication. checked the fuse at #29 and it was blown. Went to replace it and the new fuse blew before i even got in place! now the fan is going constantly as well. Needless to say battery is now dead too. I have searched all over the place and read post after post for hours today but I'm not getting anywhere. it sounds like the relay is gone. not sure how that can happen from changing spark plugs but what ever. I have no idea where to find this relay and can't find pic's / diagrams anything nor can I find a reliable method of testing. Any help on this would be greatly appreciated as I have about 9 hrs of driving to do through the mountains next week and need this issue resolved asap. Thank-you!

Pimp'n

[cesar333]

According to the manual, its in the Relay carrier E-box which is under the ECM(ecu). Engine compartment driverside.

[pimp'n]

According to the manual, its in the Relay carrier E-box which is under the ECM(ecu). Engine compartment driverside.

k. sorry... I have NO idea what the ECU box looks like which is where the problem comes in. Is it the box against the fire wall directly under the wiper blade driver side withe the three screws along the front?

[cesar333]

Yea black box right against the windshield. Its actually 4 screws. One screw is a PIA to get to. You have to take off the wiper blades. Your year might come with an access hole to get to that screw. Let me try to get you some pics.

[cesar333]

PM me your email address.

[diagnosticator]

Make sure there is No WATER in the ECU box!!

[pimp'n]

got the box open and it"s dry as a bone. i guess the next step is to replace the relay. my concern here is that the relay isn't the issue rather the result. I have looked at the harness and from what i can see it's in good shape. No stress cracks etc but would a faulty relay cause this big a short problem and what could changing the spark plugs have done to set this off? Thanx guys!

[diagnosticator]

got the box open and it"s dry as a bone. i guess the next step is to replace the relay. my concern here is that the relay isn't the issue rather the result. I have looked at the harness and from what i can see it's in good shape. No stress cracks etc but would a faulty relay cause this big a short problem and what could changing the spark plugs have done to set this off? Thanx guys!

The ECM power supply relay connects all four + BATT `12 volt red wires to the coilpacks with the key ON. You may have a short from one of those power supply wires to ground. Check continuity to ground from each red coilpack power supply wre with the Key OFF, and the relay removed.

[cesar333]

So everytime you hook up the battery the fan runs?

[pimp'n]

yes. the fan runs all the time without the key in the ignition. I had to disconect it last night to avoid killing it altogether.

[pimp'n]

The ECM power supply relay connects all four + BATT `12 volt red wires to the coilpacks with the key ON. You may have a short from one of those power supply wires to ground. Check continuity to ground from each red coilpack power supply wre with the Key OFF, and the relay removed.

the fuse blows without the key being on even (I think). I'll have to blow one more fuse and try it out again to be sure!

[cesar333]

Check your fan control module. It sounds like it has failed. Disconnect it and see what happens.

[pimp'n]

k.... would that not show up on the vag-com though?

[pimp'n]

just thought of one other thing as well. the reason i was changing the plugs in the first place was that there was a misfire in cyl 2 and 3. i replaced those plugs with an old pair just to see if there was any difference. the misfire (which was intermittent anyway) went away so I bought an entirely new set of plugs and replaced them all. could the ecm power relay going bad slowly cause a misfire issue? may be another piece of the puzzle.

[7speed]

Your problem is a corroded set harness cables that go to the coils. Peel back the wires and you will see that the wires inside are touching. Very simple fix.

[AudiA4_20T]

Your problem is a corroded set harness cables that go to the coils. Peel back the wires and you will see that the wires inside are touching. Very simple fix.

Sam FTW!

[pimp'n]

does this explain the fan going off as well? I see the point as far as the fuse goes though. Thanx.

[pimp'n]

Your problem is a corroded set harness cables that go to the coils. Peel back the wires and you will see that the wires inside are touching. Very simple fix.

k... i.m a believer BUT is there a better way to determine where the short may be? I have replaced the 219 relay and that seems to have stopped the fan issue.... good. replaced the fuse and BANG another spark show before I even got the fuse in the holder. Again no keys no nothing. I tried disconnecting the bat and replacing the fuse then reconnecting the bat and that worked until i turned the key then it went POP again. So.... i looked at one of the coil pack leads and there are 4 leads in there, none of which seem to be charged at the moment. I have a basic run of the mill volt meter that will tell me ya or na if there's power but I'm wondering if there's another type that might be able to tell if there's a short in a particular set of wires. Sorry, my knowledge on electrical is less than zero.

[7speed]

No you have to do what I said. Wires inside your coil harness have corroded and are making contact. Just bite bullet.

- Remove the rubber grommet around the boot.
- Pull the cover back and look for exposed wires
- Shouldn't take more than 1 hour start to finish

[pimp'n]

k. so it's just around the plug area it self? I tried peeling an ich of plastic back around the wires "plug back" and I could see more damage being done than good going forward. what your saying makes more sense now. I will give it a try.

[A4SoftWalker]

Could also be something simple left undone like this grounding wire shown here:
Gud Luk

[pimp'n]

Could also be something simple left undone like this grounding wire shown here:
Gud Luk

Cheers! I did check that one several times just in case but all is well. Thanx again!

[7speed]

Have you fixed it yet ?

[pimp'n]

No you have to do what I said. Wires inside your coil harness have corroded and are making contact. Just bite bullet.

- Remove the rubber grommet around the boot.
- Pull the cover back and look for exposed wires
- Shouldn't take more than 1 hour start to finish

k... lol... is there a wiki or a how too anywhere on how to re-wire the coil pack plugs? I followed your advice and it took less than five minutes to roll back the sleeves on all four and all four are DESTROYED. Complete dogs breakfast. the plastic coating has broken around the three larger wires on each plug and there are wires touching all over the place. The plug looks fine and at first glance looks like it could be rewired.

[7speed]

When I first found the problem I just wrapped the exposed wires in black electrical tape as a band-aid. I drove this way for a few months until. I found a car with a coil harness. I then just replaced it with mine. All that I did was unravel the cord and basically cut and paste each wire.

You could also just go this route.

http://www.audizine.com/forum/showth...il+pack+repair

[pimp'n]

When I first found the problem I just wrapped the exposed wires in black electrical tape as a band-aid. I drove this way for a few months until. I found a car with a coil harness. I then just replaced it with mine. All that I did was unravel the cord and basically cut and paste each wire.

You could also just go this route.

http://www.audizine.com/forum/showth...il+pack+repair

thanx. Found another one on another Audi site as well. This situation just keeps getting better. As soon as it touched the clip set up the internal plug broke into two pieces... ubber weak so off to Audi I go AGAIN tomorrow to get a few connector plugs. Again, greatly appreciate the input!

[pimp'n]

DONE! Well kinda... wires sealed and new connectors installed. The car starts and runs great first crank but my door locks / alarm etc aren't working. Is this a function of having the battery unplugged or am I missing something else? I don't see a specific fuse for security. Thanx again.

[7speed]

Yeah it's cause the battery was unplugged.

I'm not sure of the text book way, but when that happens to my car I place the key in the ignition, turn the car on then I press the lock and unlock buttons a couple times. Turn the car off, remove the key and test to to see if it works. It usually does.