Here’s an interesting map or two! On my application the Motronic ME7.2 sends a CAN message to the instrument cluster to switch off a number of LEDs around the rev counter; so called active rev limit. It’s not an actual rev limit and is just cosmetic to remind the driver not to ‘race’ the engine until it’s warmed up.
The DME hasn’t actually got an oil temperature sensor so uses a combination of coolant temperature and a signal from the oil level sensor to simulate an oil temperature.






Data on the left has this facility switched off; no oil temperature or lights switched on/off. The tune on the right has this facility switched on; oil temp sent via CAN, and the lights turn off as the engine warms up! These are the only two areas of the tunes which are changed; so these two areas control this part of the tune!
One presumes that one of these is a 1D map of oil temp ‘v’ leds on/off. There is probably a coolant temp constant in there as well. I know we are stabbing in the dark a little without a disassembly or an .ols but I am open to guesses!
Any thoughts people? Quite interesting!

Yep. BMW. E39. The M5 cluster and the X5 4.6is cluster both have the LED lights and the oil temperature gauge instead of the mpg one.
You confirm what I understand and have observed. The DME uses a ‘magic’ combination of coolant temperature and oil temperature and some sort of time factor to generate an “oil temperature” value.
The DME uses the oil level sensor to measure the oil temperature. This is one of the heated types where there is a PWM pulse applied and the time taken to cool down indicates how much oil is covering the sensor. You can also get an estimation of the oil temp from this sensor.
This calculated oil temperature is sent via the CAN bus to the instrument cluster and is used to move the needle under the rpm gauge (also accessible from the diagnostics).
The LEDs around the rpm are controlled via a separate CAN message also sent via the DME. They closely follow the oil temp but the DME controls their switch off points and not the cluster.
I bet delving into the MS43 maps may allow the LED message to be switch on. That is what I have done in the ME7.2. Luckily the 4.6is used the same DME as the car I have (a 4.4i).