Radiator fan won't turn-off
 

As some here know, my MCS has been plagued with some unexplained, serious issues. I'm getting several codes:

P0172 (too rich bank 1)

P2300 and P2303 (unknown powertrain DTC, SAE controlled ignition/misfire)

I've been troubleshooting, and still have a few items to check, so I haven't given-up yet...

Yesterday after work, she died as I was leaving the parking lot :sad: . A colleague helped me push her back onto company property. It had suddenly died as I pulled into traffic, and the fan came on and would not turn off. With my SLA battery, it drained it in not time...

My wife arrived, and after I connected the jumper cables, the fan began roaring again. I disco'd the electrical connector to take care of that, and after charging for a few minutes, she finally turned-over, and I sputtered home, about 45 minutes...

When I powered her down at home, the fan once again refused to turn off, so I disco'd it again. After sitting all day (24 hours), I decided to reconnect it (engine off), and the fan came back on...

Maybe this is good info to help me diagnose those codes...

Thanks for any ideas!

Sounds like you lost a relay...
 

check this post https://www.northamericanmotoring.co...37&postcount=9 for lots from Greatbear about the fan. It's fuse F05 in the underhood module....

Matt

Greatbear, as usual, rocks!

Thank you Matt. Hope you got my voice mails last night. I'll chat with you soon...

For those who want to see the thread in which Greatbear posted:

https://www.northamericanmotoring.co...guarded+intake

As per Bentley service book: The engine coolant sensor is located in the cylinder head next to the thermostat housing. The sensor is a two wire type whose signal is sent to the ECM and used as input to the radiator fan, fuel control, ignition timing, and coolant temperature gauge.
There is your culprit.

miminut, that does indeed sound like the culprit alright. Any idea what could cause such a failure?

I've been wanting to do an aftermkt head, and this just gives me one more reason to do so sooner...

Thank you.

Who knows!
 

Sometimes parts just fail.... But there is a way to test it. You can put your instrument cluster into "test mode" and use function 7. It will turn your odometer into a temp gauge, with the data coming from that sensor. If it's hosed, then you'll get wierd readings from it. There's a lot of stuff you can do with these functions...

http://www.mini2.com/forum/faq.php?f..._obc_functions

Matt

Matt, I actually have that link bookmarked, but I forgot about it. I will give that a shot, and like it becasue it's relatively easy troubleshooting... Doesn't the CarChip also provide this info? I'll go look, and if so, I'll log for it... Would the UNIChip impact what the CarChip reveals? Thanks again.

CarChip
 

or any OBD logger will get the very same data. I don't know if the UniChip messes with this signal at all, but if it does an erratic sensor would still give an erratic value there. But then you'd be left looking at wether the sensor or the UniChip was the problem. And didn't you say that the problems were there even with the UniChip out?

Matt

Tony,
Am sorry this happened to you. If I'd been in the South Bay, you know I would have helped. (I haven't been there too much lately.)
Bill

Matt, you are correct, that removal of the UNIChip did not make a difference. What you say makes sense, so I will give the CarChip a shot.

Hi there Bill. Good to hear from you. I appreciate the gesture, and that's always nice to hear.

I'm going to check that fuse first, then get back with my troubleshooting. Peter of M7 gave me another idea tonight also... I'll report back if indeed that fuse is blown. Thanks again.

I don't think the fuse is blown...
 

as the fan runs. It would either be a relay, or I've heard that some gizmo by the fan (hi/lo speed controller, resistors or something) have created this problem as well. Your taxing my memory!

But removing the fuse will let you park the car or drive it without the fan staying on (or coming on at all!) Watch the temps!

Matt

See this thread for more info - this has happened to quite a few people, including me!

https://www.northamericanmotoring.co...ad.php?t=31220

when my fan stuck on ....
 

had this issue while under warranty, rad' fan stuck on....

dealer told me they had to replace the entire fan assmby and that required pulling the rad' which required taking the front end bodywork off :eek2:

i figured a quick sensor or relay but they said no .... had a loaner for 3 days as i recall - but the problem went away and has not returned (knock knock)

{that's on an 02 S btw ....}

Thanks for the replies everyone. I just checked-out that link also. Very helpful... I hope to have some time this Friday to work on it... I'll report back what I find. Thank you.

[SIZE=4][SIZE=4]I had the same problem, I've enclose a couple of pictures of the faulty part:sad: . You'll unfortunately have to buy a new fan assembly, which in the uk cost £90GBP Hope this helps in some way?:thumbsup: [/SIZE]
[SIZE=4]http://img.photobucket.com/albums/08...hamxx/rad2.jpg[/SIZE]
[SIZE=4]http://img.photobucket.com/albums/08...hamxx/Rad1.jpg[/SIZE]
[SIZE=4][/SIZE][/SIZE]

Graham, thank your for the email, and for posting here! You continue to be a very nice and helpful guy.

I will have some time tomorrow to finally take a deeper look at this...

Did you happen to get the codes that I referenced above?

I wonder if this is a symptom, cause, or something totally independent of of those codes...

Thanks much! Tony

Just want to follow-up here...

I had disco'd my battery a couple days ago, and decided to reconnect it today. Upon doing so, I did not hear the fan turn on. I checked to make sure that I had reconnected the fan connector, and I had done so... Good news.

Since I knew it wasn't the coil as I had swapped it (thank Dr O!), it became very obvious that the coil wires deserved some serious inspection. I found that I had spliced into them one too many times, for various gadgets. The middle red wire was virtually cut all the way through :eek: :sad: . With a flick of the finger, I'm sure I can break it in two as it's just hangin' by a thread... The other two are in better condition, but still not that great.

I'm relieved to finally know what the cause is! How this made the radiator fan stay on, I'm not sure. But I'm quite confident this is the reason I got those debilitating codes...