Strange gearbox (maybe) issue




Sounds like a faulty door ajar sensor is kicking your tranny into Park. Use your scanner to test the sensor activity.
Last edited by CaliBenzDriver; Jan 27, 2022 at 11:07 PM.








It might not be enough to trigger the door ajar light, but enough to throw the transmission into park? The car will go into park if you open the door while moving, I believe under 5 MPH. I do remember reading a thread about this on the forum, I don't remember if it was the conductor plate in the transmission.
Is your shifter on the stalk working well, it's not sticking or stopping part way?
Last edited by pierrejoliat; Jan 30, 2022 at 08:37 AM.
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It might not be enough to trigger the door ajar light, but enough to throw the transmission into park? The car will go into park if you open the door while moving, I believe under 5 MPH. I do remember reading a thread about this on the forum, I don't remember if it was the conductor plate in the transmission.
Is your shifter on the stalk working well, it's not sticking or stopping part way?
Last edited by lizart95; Jan 30, 2022 at 08:46 AM.
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A battery tender is a must for this weather, even for me in Florida.
Last edited by S. Madman; Jan 30, 2022 at 10:03 AM.
A battery tender is a must for this weather, even for me in Florida.








The question is what in your car makes TCU decide to go from D to P?
Hands-on:
Since you report no error are logged, then exercice each suspect module to test/find a matching issue by looking at live data.
There are a dozen modules on the bus including InstCluster, F-SAM, ECU... that can create your problem.
In addition to input modules that were mentioned earlier, how about your gear selector?
Use live data from your scanner or a Xentry to get full exposure.

Last edited by CaliBenzDriver; Jan 30, 2022 at 02:55 PM.
The question is what in your car makes TCU decide to go from D to P?
Hands-on:
Since you report no error are logged, then exercice each suspect module to test/find a matching issue by looking at live data.
There are a dozen modules on the bus including InstCluster, F-SAM, ECU... that can create your problem.
In addition to input modules that were mentioned earlier, how about your gear selector?
Use live data from your scanner or a Xentry to get full exposure.

Last edited by lizart95; Jan 30, 2022 at 04:02 PM.
Last edited by konigstiger; Jan 31, 2022 at 12:05 PM.



