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RETIRED Super Stealth Moderator
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Discussion Starter #1
Yesterday, I changed the oil on the W8. I seem to recall having to replace a metal clip that holds a smallish electrical cable across the bottom of the block near the rear subframe the first time I changed the oil, but I don't remember anything about it yesterday as I was buttoning up the car.

Today on my way home from work, got a CEL. pulled the codes, as follows:

P1294 (engine cooling thermostat short to ground), P1926 (relay for aux coolant pump short to ground), P1435 (SAIP relay short to ground), P1535 (Camshaft timing adj bank 2 short to ground), P1527 (Camshaft timing adj bank 2 short to ground), P1053 (bank 2 exhaust cam adj valve 2 short to ground), P1049 (bank 1 exhaust cam adj valve 1 short to ground), and P1587 (engine mount solenoid valve short to ground) popped up.
I was betting I squeezed a cable (only on the W8, btw, in that area) between the subframe and the metal bellypan. there is no obvious damage to the cable, but the clip on the right side was hanging loose, as was the cable.

more info, now that I remember - as I pulled the car into the driveway and shut it down, the radiator cooling fans both kept running. I've never seen that happen before, even on the warmest days here in New England - and it was only a high of 75 degrees F (around 21 C) today, and about 72 F when I got home.

I remounted the cable clip to the front of the rear subframe, but that's no guarantee that it fixes it...

I'm looking for suggestions on where to start. In the meantime, I'm poring over the VCDS website.
 

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I don't have a wiring diagram for the W8 handy, but it looks like you have a power supply problem to the ECM.
First check fuses, particularly those that feed power to the ECM.
If it has an ECM Power Supply Relay, that could be faulty.
 

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Discussion Starter #3
the VCDS website is useless for the W8.

one more tidbit now that I remember, as well - I had stopped to get gas, and when I restarted the car after filling up, that's when the CEL came on. One thing I'm going to do is look at the ECU wiring, as much as I can see. I have had a mouse (most likely) or chipmunk (not as likely) problem, so there may be some chewed wires...that would suck. I am going to break out the Bentley, as well, to pore over the wiring if I find a blown fuse.
 

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What the hell is with all those codes? Half of them I don't even have in my Bentley Software manual.
I can already see I'm going to have to invest in some literature of some kind.
The only codes I have are the 15?? codes with instructions on how to chase down those problems. Other than that I got nothing.
If you need that information I can send you that, but otherwise I think I'll be watching you from the sidelines on this one. I've got nothing else to offer yet.
 

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Discussion Starter #5
all fuses associated with the ECU (as far as I can tell) are good. didn't check the ECU power supply relay, but that will be tomorrow (maybe). it's not a flashing CEL, so as long as I don't flog Molly, I should be able to get to work and back in it.

send me what you have, Dave. here's what I think happened... I am pretty sure I pinched the cable that runs under the engine to each motor mount. I did find one chewed harness that contains two wires, but those two are for the heated washer nozzles (behind the ECU case, on the firewall - if you look back that way on the driver's side, you'll see it. at some point in the near future, I'll fix that one, but it isn't causing this problem.
 

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Check how power is supplied to the affected sensors, I would guess fuse #34. Check all fuses and associated wiring.
 

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send me what you have, Dave.
Will do Jay.
I'll convert the electronic pages in the software manual to PDF's and I'll send that to you early evening. That's the soonest I can get back home and do this.
 

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Discussion Starter #9
I'd clear the codes and see if they all pop up again.
already did before I posted the original post above. they all came back immediately.

I talked to vwb5t, and he said the only place he saw commonality in those circuits was the ECU. I'll be popping the cover on the ECU this eve after dinner, and looking in my Bentley to see what I can find.
 

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PM sent with limited info. Sorry Jay, The Software version of the Bentley doesn't have jack in it.
And I'm an idiot. I was just at the VW dealership tonight picking up some parts too, completely slipped my mind to ask for a factory manual or where to get one. DOH.
I'll call them again tomorrow and ask.
 

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Discussion Starter #11
if something is broken down in a relay, it could short to a ground in the engine wiring harness E30. where are relays J496 (Aux Engine Coolant Pump) and J299 (SAIP)?
according to the Bentley, J299 is in the e-box in the fresh air plenum on driver's side, J496 location is not listed (pages Y760 or so in the Bentley).
 

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i would follow where all of those items have a common power source. could be that maybe they all branch off for each series circuit for various function and at that branching point instead of going to the devices, shorted to ground.

one thing to do first would be follow all visible wires around the engine compartment if visible. not hands-on, but to where you can examine for rodent damage, or broken insulation.
 

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Discussion Starter #13
that's why I said e30, Tom. E30 is the common ground for all of the items listed in the trouble codes, and that's why I am looking at the two relays that are supplied pickup power from the ECU (on different lines), but the coils are grounded at that same common source - E30.

a shorted (or mostly shorted) coil would put +12 volts on ground.
 

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Discussion Starter #14
just a quick question - I know these relays are supposed to be in locations 1 and 2; anybody think it would be safe to assume the relay bank under the dash on the driver's side is from left to right?
 

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Those items DO NOT have a common ground, they are individually grounded by the ECM.

A short to ground code doesn't mean that each of those items has a short to ground. It is usually caused by no voltage being supplied to them.
Note: On relays this is one of the pins that connects to the relay activation coil.

Check for 12 volts at each side of the fuse that supplies power to those items. (My guess is #34)
 

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those items DO have a common ground. that one group of circuits has a common ground at E30 (even if it connects to 87a in the engine wiring harness). note that E30 is not chassis ground, it's a circuit ground that goes to one wire in the cable run. here are the two pages in question that show all but one of the items in question for the DTCs (apologies for the rotation):





your point regarding power not being there at the supply side could be a possibility, and it is easy enough to check. not sure what fuse, tho, as the individual fuses are not listed in this diagram. fuse 34 is as good a place as any to check.

a short to ground could also mean that an individual circuit (grounded at E30) can be shorted (across the component) to E30 in the physical wire run - as in my first post, where I said I may have pinched the motor mount solenoid valve cable run. to that point, does anyone reading this know where the connector is for the motor mount solenoids?
 

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Jay, fuse S282 (10 amps, rung 154 on page 72/12) supplies power to all the devices in question. It's very likely the culprit.

Now, where is S282? It's unique to the W8, so not likely in the main fuse box! To my frustration, I've never found the key to where the various fuse numbers are located.

But, based on the splice D173 (rung 38) (S282 is fed from rung 36) being in the "engine wiring harness," I'd guess it might be in the ECM box. If not there, the relay panels is the only other place I can think of.

BTW, I was wondering why fuses are Sxxx... turns out "fuse" in German is Sicherung.
 

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OK I was wrong on the fuse number 34, but as stated that was just a guess.
There is no common ground to those items, fuse S282 supplies power to them via E30.
Follow E30 (Red/Blue wire, from your diagram) to locate the fuse, my guess would also be in the ECM box.
 

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I really wish I could help out here Jay, seeing as I need to pull the motor on my W8 anyways I could tear into all this stuff and learn along the way.
Unfortunately I moved my car to a storage spot for a while until I get some of my other stuff sold or hauled away.
I've been getting complaints from the neighbors cause it looked like a used car sales lot in my driveway.

What's sipes216 up to?
Does he have ability to dig up info from his place of employment for what you're looking for Jay?
 
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