OK so just under 2 months of Mini ownership I get a CEL and find a P0112B code. Thinking my coolant must just be low I top it off and reset the code. Couple of days later same thing but this time a puddle on drivers side. After a good search here (65,000 miles) I ordered and replaced the Thermostat housing and the crossover pipe to the water pump. Refill with new antifreeze, bleed system and good to go, right? NOT.

Shortly get another CEL (same code) no leaks ... so must still have air in system so I bleed again, top off and reset code. Good for a couple of days and same thing (still no leaks). Bottom line, I have blead the system 4 times both hot and cold and keep getting the P0112B code. I’m beginning to suspect a defective temp sensor because last time I had the scanner connected, I looked at live data ECT and saw the temp would be steady and then get erratic like going to -40 and such when I rev the engine.

Anyone have any other ideas?

 

That code is for the IAT sensor..indicating it is faulty. Inspect and or replace the sensor.

 

So what is the significance of the “B” at the end. Apparently I’m wrong but I thought that it was IAT without the “B” and ECT with the “B.”
Not questioning you answer, just trying to learn...

 

You are correct. '1112B' is ECT.. which can throw a 1111, 1112 too from what I've seen/read. Often the IAT sensor is the cheapest replacement solution to "test".. as if that doesn't clear up things, most of the time it means replacing the thermostat housing along with the thermostat.

*low coolant/engine temp will often trigger the 1112 code as well as the 1112B. Both of these codes are for "low" signal reading..not total failure.

**another user on the forum had similar experience and cleared all issues by changing the thermo housing. https://www.northamericanmotoring.co...-08-r56-s.html

 

Is the car an automatic? If so clear the fault codes in the trans control module as well as the engine control module and see what that does for you.

Are you sure the coolant temp sensor and the PCV heater connectors aren't switched around? That can cause problems. The coolant temp sensor has a green connector and the PCV heater is brown, make sure they are in the right locations.

 

Thanks for that... car has manual transmission so no issue there. I thought about the two plugs and will recheck them.
I reset the code Sunday evening but it returned Monday on my way to work less than 2 miles from home. When I got to work I had a little time so I hooked up my scan tool and looked at the ECT. I didn’t see any fluctuations and reset the CEL. Drove home Monday after work (about 11 miles) and no CEL. Drove to and from work Tuesday with no light.

Needed to drive my truck today to pick up some lumber and have to get another toy inspected tomorrow so it will be Friday before I get a chance to drive it again... will see what happens.

As soon as I get an opportunity I will check those connectors.

 

I hate it when posts just die without giving a resolution... So to not be guilty of that - the solution to the recurring P0112B code was to reinstall the old temp sensor. It could be that reprogramming it might have helped but the sensor was easy. No code in over a week now. I sort of wonder if the new sensor is defective or calibrated just slightly different? (ECS, any history on that?)
So on to the next issue, the passenger window keeps moving down even when the car is just sitting. I opened the hatch today to put some items in then opened the passenger door. When I closed it the window was down a couple of inches. Seems like when I drive it, I have to ump it back up every so often when I hear wind noise. It’s like weight of the window is causing something to slip in the mechanism.

 

Was the replacement thermostat an aftermarket unit or MINI OE? We used the aftermarket units for a very brief period and had a handful of them fail in under a year, some even within months, and have since stopped selling them.

As for the window: start with checking the battery, these cars don't like voltage irregularities, and after that I would venture to guess that you just need to reinitialize the windows. For whatever reason the windows will randomly just lose initialization and not correct for the auto dip, which just results in them rolling down 1/4" at a time.

 

Anybody got any insight on the passenger window not staying up? Seems to like to drop down 1/2” to 2” just on its own even parked. Not good during rain or snow.

 

nkfry
Oops, didn’t see your response. I don’t think the housing was an OEM MINI part - I would have to look back. I got it from ECS and I want to say it was aftermarket.

I will I’ll check on reinitializing the window. I have had some voltage issues recently after replacing the battery. I just hope it’s that simple!!
Thanks for the response and info

Dan

 

Hello,

Check the plug side, sometimes on removing the factory plug on the wire harness side the clip breaks and then does not seat all the way down in the new sensor. We had no real issues with the aftermarket ones we sell, we did have a couple with bad sensor from the factory, that about it. And we just sent new ones out and they were fine. In fact when MINI factory ones were on back order for over a couple months, some dealers and main distributors were buying from us. If you ever have a problem shoot us a PM and we will take care of you.

Also check your battery voltage, when the battery starts going all kind of weird things happen, I had it happen on my R52 and R58, both got new batteries. On the R58 the IBS was reset and it was gtg.