SRT-Tom

I am sure that most of you guys know this, but for those who don't, the Challenger's 5-speed automatic is an adaptive transmission. This means that the shift points are adjusted by the PCM for your style of driving. If you have been driving your car like a "grocery-getter," the shifts will become softer. To temporarily cure this, you can pull fuse #2.

Pulling fuse #2 for 15 seconds resets:

- All PCM DTCs erased.
- All OBD2 monitor results erased.
- All long term fuel trim adaptive values reset to Zero.

Make sure your car is turned off and the key is in your pocket while doing the pull.

Here is the technical explanation:

Long Term and Short Term Adaptives can each change the pulse width by as much as ±33% for a maximum total correction of ±66% from base pulse width calculation. Long Term Adaptive values are used during both Open Loop (wide open throttle) and Closed Loop operation.

The short term and long term adaptive have a larger effect on engine pulse width than a lot of the other parts of the equation (ECT, IAT, MAP, RPM).

Short term adaptives are controlled by the rear O2 sensors so this is where your air/fuel mix will be tested and adjusted by the PCM once the engine is at minimum operating temperature (192-199 deg F). Short term adaptives will clear once you turn off your engine.

Long term adaptives will begin to store once the engine is at operating temperature (192-199 deg F). After the vehicle has reached full operating temperature, short term correction factors will update Long Term Adaptive Memory cells based on vehicle load (RPM/MAP) to allow the Short Term Adaptive value to be brought back to near zero. Once this correction factor is updated in the memory, it will be used by the PCM under all operating conditions, open loop and closed loop.

During open loop operation (wide open throttle, when your foot has the pedal planted to the floor) the PCM adjusts injector pulse width to supply a predetermined amount of additional fuel, based on MAP and RPM (and long term adaptives based on the above).

A photo of the 2009 model fuse box showing the 25 amp beige fuse is attached.

Attached Images

fuse box.jpg (50.3 KB, 11 views)

SRTSammy

Never drive mine like a grocery getter...

Unless I have groceries in it!

__________________


Scott

Storm Rider

I am always having someone with a bumblebee muffler starting stuff that I have to finish.

__________________


Challenger - Back from the Dead