I just got a check engine light and got 2 codes: P0101 and P0128.

P0101 comes back to the Air Mass Meter (that I just replaced about 18 months ago). I'll try cleaning the sensor, but if anyone knows any other info on this it will be greatly appreciated. I would like to avoid spending $300 on another Air Mass Meter.

P0128 says the that the "input from the coolant temperature sensor indicates a temperature value that is below the thermostat regulating temperature." I think I just need to replace the thermostat, but I would like to know for sure.

Thanks for your help.

 

This may sound dumb, but did you check the connector at the MAF. I forgot to reconnect it and although the car started ok, codes such as yours popped up when I checked them. Reconnected the plug when I realized what I forgot, and voila, good to go.

 

This may sound crazy but did you buy this MAF from a MB dealer wrapped in a blue box or did you find this for cheaper on the internet somewhere? Cleaning the MAF won't help a P101 error, it's gone. Many people have gotten tricked on ebay where a seller has clone MAF's that don't work. They are silk screen with the correct part number but are duds. Like Richard said, it may just be the connector, try spraying electronic cleaner in the connector, make sure it's good. Also, if you OBD2 scanner allows, get some readings at idle and at different RPMs and match it up with someone with the same motor and see how far out of range it is.

The P0128 I got a long time ago on my 2002 C230 and it was the thermostat, especially this time of year. What would happen is the thermostat would stick open and it would take longer than the ECU expected to warm up and throw the code.

 

i would recommend ebay uk for certain hard to find parts like tht cheaper and mb oem or if u have a friend like mine who lives in ontario ask him to give you the dealers number