No Fan response. ECM-6100 Topic is solved

Jonesroad · Post by **Jonesroad** » 19 Dec 2022, 20:05

Hi all.

Bought a 2010 v50.
Previous owners told me that the radiator fan had been hot wired. Had a wire going into the fuse box, hooked to a relay, then to the fan. polarity was reversed so the fan was blowing backwards.

I took all that off.

The car has an ecm 6100 code.

I have a 2011 s40 t5- so I took the v50 fan off, tried it on the s40. activated it with my scan tool. No it's not a dice unit but it's a nice autel that has almost everything besides flash capability. Fan worked fine on the s40.

I went back over to the v50 with that fan , along with ANOTHER fan I pulled off yet another s40... so two different fans- nothing. The cool can not operate it. AC does not make it come on. There's no response.

I have pulled all the wiring wrapping off and traced it visually.from fan to fuse box to ecm. I've jumped from the ecm wire coming out to to plug at the fan. I've checked continuity, resistance, checked for voltage. The wires all looked good. the power wires going to the fan have voltage.

The only thing I noticed different , was that the fully functioning s40 ecm has 3 volts..ish.. coming out of the ecm when the key is in position II/ accessory mode. The crap black v50 turd has nothing in that same position. That is the only difference I've seen as far as function.

I did notice if i lightly tapped the ground wire ..i could make the fan briefly come on- which I believe was just recreating a pulse. if i held it on, nothing happened.

I've seen what all the possible causes of this listed under error code 6100. It's all shorts or opens right? I keep hoping there's something ridiculous i'm overlooking and not ..a busted ECM.

I switched coolant temp sensors with the s40.

Hopefully I've remembered everything I've done up to this point correctly- been spending several days on this. When I got it I thought oh this will be a quick fix, but turns out I was mistaken. I've been searching the forums this swedespeed , saw one on the scanner danner forum ] about the 6100 code but ..someone had the wrong harness. I don't think that's my case here.

Anyways- If anyone has any suggestions I'd sell off part of my soul for any direction.

Post by **RickHaleParker** » 20 Dec 2022, 18:27

Jonesroad wrote: ↑19 Dec 2022, 20:05
It's all shorts or opens right?

1. Shorts and opens.
2. Obstructed fan motor.
3. Damaged fan control module.

Jonesroad · Post by **Jonesroad** » 21 Dec 2022, 08:51

RickHaleParker wrote: ↑20 Dec 2022, 18:27
Jonesroad wrote: ↑19 Dec 2022, 20:05
It's all shorts or opens right?
1. Shorts and opens.
2. Obstructed fan motor.
3. Damaged fan control module.

well I know #2 and #3 is out of the question- I tested two fans on it- the bad car v50, then on another car- the good s40 ...plus the original fan on the control/good car/s40- all worked. all turn on with the tool.Three different fans on the good car.fan on on top so nothing can touch it.
V50, no response from the tool. No response when hot. No response from AC turning on.

your #1.. I have checked continuity voltage grounding so much I'm starting to feel like a nut I've read the description of the dtc but still... I just can't see how it is that when i'm getting good connection between everything.

Post by **RickHaleParker** » 21 Dec 2022, 16:24

It is a pretty simple circuit. Check your inputs and connections. Are you getting a signal from the ECM?

: V50 Fan.png (76.49 KiB) Viewed 2651 times

Jonesroad · Post by **Jonesroad** » 21 Dec 2022, 17:02

RickHaleParker wrote: ↑21 Dec 2022, 16:24 It is a pretty simple circuit. Check your inputs and connections. Are you getting a signal from the ECM?
V50 Fan.png

God almighty. Looking at that page- I was thinking..why does that diagram look slightly different from the one I've been seeing?
I realize now , my wiring diagram was TP3978202 - the 2005 version. Your diag. is 39150202. 2010.
I've been checking continuity back to b:7 on the ecm. It's actually supposed to be B:79 Jesus help me. I'll check see what is going on. I might have made a completely idiotic mistake of the wrong wiring diagram wondering how it wasn't adding up.

I did notice not all the screws that secure the ecm to the breather box were in there. I kept thinking about that, wondering why. Someone fooled with this car more than I realized.

Jonesroad · Post by **Jonesroad** » 22 Dec 2022, 16:08

update:

So i was definitely looking at the wrong wiring diagram.

But also, that fact didn't slap me in the face because someone has apparently put in a wiring harness from an older car- so the pins in the harness were matching what I was looking at, which was the 2005 or 06 wiring diagrams.

I moved the wire over..well actually broke the wire/ pulled it out of the little end- so I just stuck a big push pin through the whole which was empty. Turned on the ac, fan came right on.

Fan is still not coming on when the engine gets hot- but i imagine this is probably due to the fact that the harness is not correct. Something coolant sensor related I imagine. but, at least the head scratching part is over..the 6100 code is GONE .

Thanks so much RickHaleParker for the updated wiring doc! I would have probably still been out there scratching my head!

Post by **RickHaleParker** » 23 Dec 2022, 15:28

Jonesroad wrote: ↑22 Dec 2022, 16:08 Something coolant sensor related I imagine.

Probably the original root cause which was misdiagnosed.

Jonesroad · Post by **Jonesroad** » 27 Dec 2022, 10:56

update= The car won't voluntarily switch the a/c on once it gets up to temp.
It's reading temp out of the obd port, I tested resistance on three different coolant sensors, all were similar but went ahead swapped a sensor just for whatever reason.

Car gets to temp but i won't turn on the fan. If I turn on the AC fan comes on- then after I have turned off ac the fan will stay on for a minimum of two minutes- so far today longest it stayed on was about 8-9 minutes. So the ecm knows to bring it down to temp and to continue running even after ac is off.

Set amount of time goes by, fan goes off.. then unwilling to switch on.

I'm leaning towards possible ecm fault ..similar to how I was at the beginning when I had wires going all over the place.

coolant temp sensor wires are the same on the new wiring diagram as they were on the older 2005 version, so that isn't an issue.

Thinking maybe it's time to break down go ahead by a proper dice unit and see if programming will do anything.. not sure what else to do at this point.

I'll update later as i progress.

Jonesroad · Post by **Jonesroad** » 28 Dec 2022, 05:41

alrighty folks. last one.

fan wasn't coming on..because I wasn't letting the engine properly get up to temp. I know that's idiotic, I would've sworn bet my soul it came on at 102. It kept raising up, I have an unreasonable fear of these things blowing head gaskets. Most of these volvos that I buy are because of just that. tired of doing head gasket jobs. So I kept engaging the fan.

Finally got brave..it comes on at 106.

So case closed- ecm works, fan works, who knows what else in god's name might not be wired properly