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HELP: P/R/N/D has vanished from my display...without three bars of death! Car won't start or move out of P.(TCU)

6242 Views 26 Replies 10 Participants Last post by  Sal marinosci

2008 fortwo cabrio with 49k miles and a fresh battery that was just tested.

Worked fine all day...then PRND on dash display. Also won't start or switch out of P. Yellow button trick allows it to go to RND but still won't start and locks up again once put back into P.

Doesn't turn over or even try to start. It is as if it can't see its transmission.

Swapped clutch actuator... no difference. Checked main fuse...load tested change. Edit: I plugged in my relatively simple/cheap OBD reader and it showed no faults.

What would make the PRND disappear?

Thanks, -Eff
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The fault may be in a system it can't access.... :)
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Rather than try and DIY this, my recommendation is find a local shop that does Mercedes work and has a Mercedes STAR machine and let them check out the car. It may cost a little more but they can pinpoint the problem and save you money in the long run. Just my .02. :)
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I have another version of that, it's a good scanner for Mercedes cars. Just occurred to me, have you tried the transmission "teach-in" procedure? No guarantee it will do anything, but it's free....
Teaching-in the transmission system:
X Stop the vehicle in a safe location.
X Move the gear selector lever to park
position P.
X Turn off the engine.
X Wait at least 30 seconds before
X Press the brake pedal.
X Restart the engine
Three bars instead of P appear in the
multifunction display.
X Wait at least 30 seconds.
The transmission is taught in.
When teaching-in was successful: P
appears in the multifunction display again
and normal transmission operating is
restored :)

Ignore all that - I see the car won't start.....
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