Shifting problems
 

After going through the many threads regarding transmission issues, I have yet to pinpoint exactly what my problem is. I have a 99 ML320, that is out of warranty. A very good friend of mine is a ASE master technician and he is helping me repair the vehicle. He has the scantools to extract tranny codes, so I have those codes available to anyone who could help me out.

Anyhow, a couple months ago, every couple of days the car would either not shift up into a higher gear, stuck in 2nd gear it seems, or get stuckin 3-4th gear, and will not downshift when vehicle has slowed down to a stop. This means at a stop light it would accelerate extremely slow due to the higher gear. I would then turn the car off and turn it back on, and the problem would be gone. Back to normal.

A couple of days ago, the problem has came back, but this time, it is here for good. I tried turning off and back on to no avail. So right now, it wont upshift past 2nd gear. I initially presumed it was limp mode related, but my friend says there is a code in the tranny cpu saying that it has to do with the RPM sensor. I could get the exact codes if that would help.

Could the RPM sensor cause the tranny to stop shifting? I'm open to any ideas any may have

Thank you,
xbrxx