ACC plant mode

[Thorium]

I recently had my dealer perform the TSB 08-004-09. (the ACC had previously been disabled.) When I got the car back the firmware was updated, but the ACC still appeared to be disabled. (ACC not possible to activate, but not throwing any faults). Normal cruise control was fine.

I stopped by the dealer a few days later, to get the the ACC enabled, hoping for a quick fix.

No joy! When I got the car back it was stuck in "ACC plant mode", the normal cruise control did no longer work, and the dealer said it would take 8 hours of labour to get it out of plant mode, because the the sensors would have to be calibrated. (!?)

At the moment I have no cruise control, which is straining my love life with my 300C.

Anybody familiar with the elusive "Plant Mode" that takes 8 hours of mechanic time to get out of?

T.

[Thorium]

It looks like the ACC plant mode might not be widely understood, there are no responses so far and there is no information on the net.

A wise man told me that the vehicle might exit "plant mode" after 3 driving cycles or so. He defined a "driving cycle" as starting, warming up, stopping and completely cooling down the engine. I have not had any results so far, but I am still hoping.

Whatever happens, I will post the the outcome in this thread, maybe somebody else in the same situation will find it useful.

T.

[Thorium]

I just took my 300c to the dealer for the third time, and they explained a bit more about the ACC calibration. In short, at best it would take them maybe a day to do it, and at worst they didn't even have the tools they would need. They did offer to disable the ACC and re-enable my ordinary cruise control.

I consider my ACC a write-off at this point, so this is probably what I will do. It sounds like I could buy a new ACC system for the cost of calibrating the old.

[Thorium]

(I keep updating this thread for the sake of others with similar problems. )

No calibration necessary!

The problem was between the dealer and the firmware. "The firmware didn't take", according to the dealer. After resetting everything back to factory defaults, and re-flashing the firmware the TSB firmware upgrade was completed. Cost me $100.

I'm happy, I've got ACC and no "plant mode".