How to clear the PCM

[offroadaz]

I was looking for this other day on how to clear the computer in the jeep. This not only clears your codes but forces the computer to relearn your driving styles


Forced Flash

This very simple procedure will Erase the “Adaptive Memory” stored inside the TJ PCM and allow a new “Adaptive Memory” to be developed.

After performing this procedure the PCM will re-learn and store into Adaptive Memory your engines performance characteristics.

Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.
Reconnect the Battery Cable
Turn Ignition Switch to the “On” position but DO NOT start the engine
Turn Headlight “On”
Turn Headlights “Off”
Turn Ignition Key “Off”

Adaptive memory has now been flashed, or erased from the PCM.

When you start the engine it will be running off a set of pre-programmed tables that come with the PCM from the factory.

When you get the engine up to operating temperature the PCM will start to collect data for the “Adaptive Memory”.

The PCM will collect data for Adaptive Memory for the first 50 Warm-up Cycles.


Warm-up Cycle

A warm-up cycle happens when all of the following conditions exist.

Engine is running
A raise of 40F in engine temperature must occur ABOVE the engine temperature at start-up
Engine Coolant Temp must reach at least 160 F.


Once your engine has gone through 50 warm-up cycles in at least a 500-mile distance the PCM adaptive memory is set.
It WILL NOT Change unless you flash it out and start all over again.

[Spshlj]

What is the significants of doing this?

[AZLugz]

For the adaptive part. Not sure if the TJ trans is the same but the transmission in the Commander is an intelligent adaptive Electronic controlled unit. It learns your driving habits and adapts its shift points and torque to match requirements. This is especially helpfull with towing my trailer with the quads as it learns so it holds in gear longer on hills so the RPM's are not so low when it shifts that it bogs way down

[offroadaz]

Im pretty sure its the same on the new TJs too

When I swapped out my tcase and when I replaced the 02 sensors I reset the PCM.