2005 S40 Tach reads too high

atikovi · Post by **atikovi** » 02 Oct 2013, 11:48

I haven't driven the car over a month so I had to jump start it a few times. Don't know if that has anything to do with it but now the tach reads 1,000 rpm too high, and with the engine off, it points to 1,000. Can the tach be adjusted with a scan tool?

difflock54 · Post by **difflock54** » 05 Oct 2013, 16:34

The CEM needs to reset after the power failure due to flat battery.
Simple way is to remove both of cars battery terminals and hold them together for approx 15-30 seconds.
Then refix them to the battery posts, (correct polarity of course) and it should be okay.
Radio code needs resetting though also.
Sometimes simply driving for a reasonable distance and time also alows the CEM to reset itself.
You know then the rpm gauge reads normal idle rpm's. (approx 750-800)

atikovi · Post by **atikovi** » 05 Oct 2013, 19:59

Yes it took care of itself after a few starts.