ECM-6300 and ECM-6B00 2000 V70R [BAD Battery to fusebox supply cable!] EPIC Troubleshooting Topic is solved

[abscate]

I've never been totally stumped by a car before, this is a first.

Fixed that quote for you. Congratulations.

Persistence is the first cousin of perseverance.

Please do the honor of either checking the green box

[abscate]

I'm sure you have already checked or swapped the B+ cable in the main fusebox and the electrical portion of the ignition switch?

The B+ cable can look ok, but undo the nut in the fusebox and look at the cable under it. Mine looked ok, but found it had almost totally melted and had bare areas that could potentially short out.

Not sure if it would help, but I have a spare ECU from a 2000 V70R, and also a ETM from a 2000 V70XC that I had connected to my 2000 V70R as suggested by precopster to see if it worked. It whined like a good un so should be good. Also think I may have a good electrical portion of an ignition switch. If you fail to get any further I can send the parts for you to swap out on a trial basis. I would like them back as they are my back up stash.

Neil.

Awarded this year of our Swede 2019 for nailing it..

[bmdubya1198]

I knew I'd figure it out eventually, it was just really getting on my nerves... I'm a little annoyed that it took me so long, but I'm happy to have this behind me! I wish it also fixed the whiny ETM, but I'm fairly confident I can have that fixed today.

Neil gets the honorary "topic solved" for his post! Shame on me for not checking that terminal more closely earlier!

[scot850]

Thanks for the thanks, but glad you got to the bottom of the issue eventually. It is a strange issue with the B+ cables. Seems to affect the 99/00 'bastards' more than earlier ones for some reason, although earlier cars are not strangers to the issue as well. I have read of cars going on fire and underhood fires caused by this issue, so all take heed and been warned! Check carefully!!

As to the whining ETM, maybe it is just like that? These 'R's are needy cars so how better to keep your attention than whine all the time!!

My ETM also whines but only for a short period after turning the ignition key. Did you try another ETM to see if it does the same?

Neil.

[abscate]

I think there is a whiny ETM thread going on this one.

I’ve noticed on my 99 I had to remove all the relays and clean heavy oxidation off the spade terminals twice over 20 years. Maybe humid air is reaching the box on these, redesigned from -1998?

[bmdubya1198]

I'm not sure, I almost feel like the noise is between the firewall and engine now. But sound travels, so I can't confirm. Weird...

[bmdubya1198]

Aaaaaand just what I wanted to say a year later... IT'S BACK!

Thread over on Swedespeed, but just to update this one, it's the same situation as before. CEL is on now for P0455, and it's flickering just as it was. No ETS light this time around, although while cranking, it does flicker since it's on during the warning light test.
While testing things though, I noticed if I applied a test light to the signal wire for the CEL, it stopped flickering. How does it show signal too low/short to ground, yet pulling more current on that circuit eliminated the problem? Hmm...

[abscate]

Because you are loading a potentially complex transistor circuit , not a simple DC one. The CEL is triggered by being grounded through the Q on the ECM board somewhere, in all likelihood

Clean all those grounds, clean those B+ terminals

How is battery age and HISTORY?

[bmdubya1198]

Battery is maybe 6 months old, never any issues with it. I'm thinking about making a new ground cable for the battery too, it's looking old.

[bmdubya1198]

Does anybody know if the signal from the ECU for the CEL is supposed to be power or ground? The diagrams aren't very clear. It almost looks like the alternator D+ wire should be the supply and the ECU will ground the CEL circuit to illuminate the bulb. I have perfect voltage from the alternator (14v at idle) so that's not an issue. When I checked continuity to ground on the CEL wire, it was flickering from open circuit to 0 ohms consistently with the flickering. Voltage is very low, less than 1v.

I have voltage on the ETS wire, and that isn't illuminated. It seems that it has battery voltage when the light is off, then grounded when it's on. What I don't understand though is how VIDA tells me there's a short to ground, yet it's SUPPOSED to be grounded? I really have no idea what's going on here. All I can think is that the driver for the CEL and ETS light in the ECU are dead. I really don't want to drop the money on testing that theory unless I'm absolutely certain, though.

There doesn't seem to be a problem with any grounds. I'll do another voltage drop test on the battery grounds today with the engine idling. Last time I tested it, there was VERY little drop, only maybe 2-3 mV.