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

[bmdubya1198]

I emailed Hilton the other day, he told me yesterday not to worry about those codes for now being that they aren't causing the low boost issue. I'm still concerned about them... this car has too many weird electrical issues to just ignore it. I still haven't figured out why it was running like it had a bad ETM a month or two ago when I did nothing to solve it. I pulled the cluster again, put it back, and since then it has been perfectly fine aside from the usual problems.

As far as I know, the code wasn't there before. But I couldn't tell you for sure, I didn't have VIDA until this March. I'll have to see if I screenshot-ed the OBD2 codes before the swap, or at least before my wiring work. I know I checked it with Torque at some point. That way I could totally rule out my wiring work... I hope so, that should simplify things.

[bmdubya1198]

After digging through screenshots I took from the codes, I couldn't find much from before I removed the TCM wiring, so I can't totally confirm that the codes were not there before. I think this would be a good time to reiterate the issues I'm having and cut out the nonsense to help make this a little easier...

The codes are...
ECM-6B00- Malfunction indicator lamp (MIL) - Signal too low
ECM-6300- ETS warning lamp - signal too low

In my most recent check with VIDA, I also saw two ABS communication-related codes, don't know if they're related but I'll add them in anyway...

ABS-0092- Control module communication Control module communication
ABS-0095- Control module communication Control module communication

The symptoms are as follows...

-ETS light and MIL will flicker or pulse if they are illuminated. They do NOT do this if I manually illuminate them in VIDA, it only happens if there is an error and it throws an OBD2 P-code.
-ETM whines/moans while the engine is idling. It's very loud and sounds like a weak fuel pump (frequency changes, but it doesn't shut up). The MIL and ETS light only seem to flicker when the ETM is making noise, which is why I assume this is related to the root issue, although I cannot confirm.

I have checked all wires between the ETM and ECM, so I don't believe there is an issue there. I have gone through fault tracing steps in VIDA for the codes, and they were basically useless (check the wires between the CDM and ECM, blah blah blah... needless to say there's no issue from what I've found). ETM has been replaced 3 times, so that's not the problem (faults and symptoms have not been affected).

Fortunately someone on Facebook who owns a Volvo shop here in NC was kind enough to offer some help, but as always, I like to give as many people as possible an opportunity to offer input. You never know if someone else has run into a similar issue (although that seems like a far reach here, apparently my car is the ONLY P80 ever to have an issue like this).

[wizechatmgr]

Also check and verify the grounds on the ECM, block and to ETM. I'd be willing to bet you're going to find some sort of shenanigans.

[bmdubya1198]

Also check and verify the grounds on the ECM, block and to ETM. I'd be willing to bet you're going to find some sort of shenanigans.

Yeah, I’ve double and triple checked all grounds, no issues to be found. I was really expecting an issue with the ETM ground, but it’s fine.

[wizechatmgr]

Also check and verify the grounds on the ECM, block and to ETM. I'd be willing to bet you're going to find some sort of shenanigans.

Yeah, I’ve double and triple checked all grounds, no issues to be found. I was really expecting an issue with the ETM ground, but it’s fine.

I'm almost out of ideas... conjecture follows:

To me the sound you hear is the ETM telling the stepper drivers to lock up (hold at full strength) or to go to a position it cannot achieve. I'm unsure if a stepper is used in the ETM, it's all speculation on my part, but it would make sense. I just know if you command a stepper driver to do something it cannot, it will try anyways unless the firmware involved catches and prevents it - ie, reading a position sensor and comparing it to where it believes the current position is.

Double check your accelerator pedal position via VIDA - should be two values, both at alternate ends of the measurement scale. Compare those to the ETM's value. I had an occasion where mine sounded like it was singing because somehow the ETM's position and the pedal were not in sync - I believe I exited a ETM diagnostic uncleanly (i.e. key off in middle.) I would restart the car and it would start and die then whine loudly. Finally I left the key on for 30 minutes with the key to on but not running with a small battery charger attached, it eventually started working upon the next attempt and I've had zero issues since. Place your hand on it and make sure it isn't heating up before doing so.

[bmdubya1198]

I'll try to run the ETM diagnostics again to see if that makes a difference, but this theory makes sense. It does sound like it's struggling to achieve its rest position, because when I rev the engine it seems to go away, then when it returns to idle it starts whining again.

When I look at the potentiometer values and the absolute throttle position, everything is pretty even, within 1-2%.

[wizechatmgr]

I'll try to run the ETM diagnostics again to see if that makes a difference, but this theory makes sense. It does sound like it's struggling to achieve its rest position, because when I rev the engine it seems to go away, then when it returns to idle it starts whining again.

When I look at the potentiometer values and the absolute throttle position, everything is pretty even, within 1-2%.

Check and verify the position of the throttle plate - it may have gotten gummed up or is binding on it's way to its rest position.

[bmdubya1198]

I'll have to check it out. I've never disassembled any car as many times as I have with this one!

[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.

It looks like Neil nailed this. How I missed basic B+ checks throughout this thread, just sad.



Its amazing how esoteric failures can be simple 12V supply

It’s reall difficult to diagnose wiring by resistance measurements btw. Voltage drop is the way to go. Most multimeters don’t have the sensitivity for reliable resistance drops. In addition, digital meters, which “ have to better ,right?” Sample at a few Hz, so intermittents are missed.

[bmdubya1198]

It looks like Neil nailed this. How I missed basic B+ checks throughout this thread, just sad.



Its amazing how esoteric failures can be simple 12V supply

It’s reall difficult to diagnose wiring by resistance measurements btw. Voltage drop is the way to go. Most multimeters don’t have the sensitivity for reliable resistance drops. In addition, digital meters, which “ have to better ,right?” Sample at a few Hz, so intermittents are missed.

Indeed he did, turns out that's exactly what was wrong! Hopefully those codes stay away. Now to figure out ECM-912A... I'm going to check the ETM power supply wire shortly. I may go ahead and make a new B+ starter cable today since I'll have the space while replacing the intercooler.

Voltage drop is definitely a more reliable test than resistance. I've found that with my Craftsman multimeter, it's not going to be accurate enough to ohm out wires effectively. I'll see people say a particular wire should be no more than 0.01 ohms, meanwhile the lowest my meter will go usually is around 0.6, even on a brand new short strand of wire which should certainly be 0.01.