Hello everyone,

My car (R56 Cooper 2007) currently has two issues. Nothing too serious, but I’d really like everything to work properly.

The first one, which seems to be the least serious but may be related to the second, is the following:
The temperature displayed on the dashboard is very far from the actual temperature. When I start the car, it’s more or less normal, but as I drive, the displayed temperature decreases and after about 5–10 minutes it becomes completely inaccurate (and well below the real temperature). After that, it rises slightly but still remains a few degrees (Celsius) below the actual temperature.

I have replaced the temperature sensor with a new one and checked the wiring harness — everything seems fine.
When I read the temperature via the OBD port using a diagnostic tool, the sensor reports a correct temperature, which does not match the one displayed on the dashboard.

Do you have any idea what could be causing this?

Second issue: the cold idle is a bit unstable, and when the engine is warm, the idle speed drops a little too low and then comes back up and stabilizes at normal speed. The more the engine warms up, the less noticeable this idle issue becomes.

I recently replaced the air pressure and temperature sensor on the intake manifold. I also recently replaced the entire timing chain (the problem was already present before; it’s slightly better now but still there). I reset the values using ISTA.

Again, do you have any idea what might be causing this?

Thank you in advance!

 

Turbo S or non-turbo Mini?

Can you post a picture of the display temperature that you are referring to? Can I assume that it is the ambient outside temperature?

With respect to the unstable idle, please post all the current fault codes.

 

This is a non-turbo.
The temperature display is the ambient outside temperature.
And there is no fault code (just a problem with DAB antenna).
I can post pictures tomorrow morning (I'm in France, 00:15 at time time )

 

Have you checked for DME fault codes relevant to the unstable idle? Good night!

 

DME has no fault codes (I read fault codes with deepOBD tool and confirm with ISTA). No fault code on DME, just ONE fault code on all the units : The DAB antenna.

 

Regarding the unstable cold idle, are the coolant temperature sensor readings via OBDII expected or unexpected?

 

Temperature this morning : 2°C. The night was cold.
When I read temperature with OBD, I have the following lines on my App : sensor : 2.00°C. Dashboard : -6.00°C.
When I read the DME fault codes, there are still no errors reported.
The coolant temperature seems correct, oil temperature too. -2.00°C to 58.50°C for coolant, -2 to 44°C for oil. Air intake : 0 to 8.25°C. For DME, outside temp is -6 as reported on dashboard (but not by outside temp sensor).
It was cold this morning, and the engine ran normally, including the idle. I only did a short drive and didn’t have time to let the engine fully warm up.

 

My Launch scan tool can report both the raw (input) outside temperature data received by the IC control module and the processed (output) outside temperature data shown in the display.




I assume that your posted OBDII reading of outside temperature is the raw data. If you can also read processed data via OBDII, the expectation would be that it will match the erroneous display reading. If so, the issue is likely a faulty instrument cluster control module.

 

Yes, I wasn’t precise. I get 2°C from the direct sensor reading, −6°C from the OBD reading, and also −6°C on the instrument cluster.

I thought the KOMBI module relied on several data sources to determine the temperature to display, but apparently not—I’ve just read that it doesn’t. It’s simply doing some rather sophisticated calculations to determine the displayed temperature.

Excerpt from BMW/Mini documentation:
" The signal from the outside temperature sensor is digitised in the auxiliary instrument. A calculation model suppresses the effects of thermal radiation from the engine compartment on the signal. At higher driving speeds and lower engine temperatures the system selects lower damping action. The real outside temperature value can only be reliably expected starting at driving speed of about 80 km/h. "

There is probably a problem in the KOMBI Module. I will try to change it.

 

My understanding of the circuit:
Circuit diagrams in the Bentley service manual show that the two wires of the outside temperature sensor send raw temperature data through (1) connector X15 to (2) the tachometer/additional steering column instrument and then to (3) the instrument cluster (IC/KOMBI) control module. The IC control module processes the raw data and sends the processed data to the display.

Maybe the slightly unstable idle reflects the early stages of the DME relearning new adaptations.

 

Yes, you are right, I was calling KOMBI the tachometer unit (which seems to be called KOMBI2).
For the idle, the adaptations values were reset 4 or5 weeks ago (and 6-700km) so I think that new adaptations values are stored.

 

Any chance that some air trapped in the cooling system is interfering with temperature readings from the coolant temperature sensor? I'm trying to think of idle issues that would not throw DME fault codes.

Have you tried running DME data streams for operational smoothness values?

 

I will bleed the system and monitor the cylinders to see what happens.
Thanks !