BMW 545i 2005 with 86K miles:

Hi, I keep on getting Code P112B but this code is not mentioned in the BMW 5 service BentlyPublishers service manual. The car seem to run fine but does anyone have any idea what this code is all about? The check engine light only gives out the usual "increase emissions alarm".
My cheap ODB2 scan tool (Maxi Scan MS 300 does not even recognize that code, it simply says there is an alarm with code N/A, but when I asked the guys from AdvanceAutoParts they did read out the code for a little tip but also could not tell me what this is about. Every time I reset the code it comes back after the first or second drive cycle. I found in another forum (I think Mini Cooper that this code has something to do with the coolant but I am not sure if codes from the Mini Cooper are related). Nevertheless the coolant is full and I can't find anything wrong. Please help, the check engine light drives me crazy and I don't want to go back to BMW due to cost reasons.

 

Found this online: P112B - Engine Coolant Temperature Sensor 1 Minimum Temperature Implausible. Maybe one of the sensors?

 

Many thanks for the tip! Where did you find the complete list of all BMW E60 codes? I was also looking around but I can't find a full list including code P112B. As mentioned, it is not listed in the Bentley BMW Service Manual for the 5 series.
Nevertheless, I just ordered an engine coolant temperature sensor (ECT) really cheap of Ebay (~$15) and will try to replace it. Hopefully this is it. What I am not sure about is if there are additional coolant Sensors. I only found one on the front/middle of the engine . I will report back if this works.

 

Hi, replacing the coolant temperature sensor fixed the issue

here is a short DIY:
The sensor is on the front center of the engine
- get spare part of your favorite site: 13 62 1 433 076 (for example $14, free shipping of Ebay, first picture)
- measured about ~1900 Ohms at room temperature, (second picture)
- let engine cool off a bit.
- disconnect sensor cable, take old sensor out replace with new one (you need deep socket, 22 mm - the alternative FAE sensor requires a smaller socket), some coolant will leak out. It is a easy procedure.
- measured about ~600 Ohms in the very warm engine block (third picture)
- reconnect cable, top off lost coolant, reset and clear code from memory, and off you go.

I am still looking for the link that shows the ENTRIE set of fault codes including P112B and others that may not be so obvious. Anyone who can provide the full link?

Thanks

 

I found this for the Mini, but may also be applicable to BMW.

ECU Codes Chart - 2nd Generation MINI - Library