One problem related to automatic transmission control module has been reported for the 2004 Jeep Wrangler. The most recently reported issues are listed below.
At 91,500 miles the pcm failed for a second time. I am not certain when the first failure occurred, but it was shown to have been flashed previously. This issue surfaced in the form of a stall out at a light. When attempting to accelerate from an idle position the engine stalled. After parking the vehicle, turning over the engine while simultaneously giving it gas, the vehicle turned over. According to three different mechanics this is a common issue among '04 Jeep Wranglers that they have encountered recently (12 years after market and 2 years completely out of warranty). No one can find a replacement pcm because they are no longer manufactured, and it was Chrysler's recommendation that customers experiencing this issue go to a scrap yard to find a replacement (likely to have the same issue). As a customer I am appalled that we are aware of this issue and there have been no recalls. Driving down the highway my battery charged to 20 volts and could have exploded.