Welcome to the wonderful world of Jeep. I will save you a bunch of looking. Have the PCM replaced, tell the place doing the replacement to verify they are using the latest update to flash the replacement. Oh and to attempt to keep that transmission happy add an extra cooler. This is a common problem with the 2003-2008 Jeeps that do not have CVT or manuals.
STAR Case Number: S1421000016
Release Date: 05/20/2013
Transmission Temperature Warning Lamp Illumination along with DTC P0218 High Temperature Operation Activated
1. As identified in TechCONNECT s diagnostics for P0218:
a. Verify proper engine cooling system operation which would affect proper transmission operation.
B. Verify proper torque converter clutch operation.
2. Was an issue identified with the transmission cooling system or transmission?
A. YES>>>Repair as necessary.
B. NO>>>Proceed to the next step.
3. With the scan tool, check the Event Data to help identify the conditions at which the DTC was set.
4. Did the Event Data recording indicate an unlikely situation (E.G. Transmission Temperature at +127oC. (+260oF.) And Engine Temperature at -20oC. (-4oF.)?
A. YES>>>Replace Powertrain Control Module (PCM)
b. NO>>> The customer s driving pattern may indicate the need for an additional transmission oil cooler.
Saturday, June 10th, 2017 AT 3:15 PM