It's a long story but here's the story so far. 2005 TJ Sport, 42RLE.
I was out on the trail and noticed the transmission shifting notably harder than usual. No CEL, no codes that Torque could find. Everything else was fine and the Jeep was driveable, but after I got off the trail I took it in to a local transmission shop and got it checked out. They said the transmission temperature sensor was being flaky, and there was a (hidden) code in the TCM for problems with that sensor, so they swapped out the sensor. While they were in there, they gave the mechanical parts of the transmission a clean bill of health, so it seems like that stuff is in decent shape.
Not long after, I was out on a trail doing a moderately steep hill climb and noticed the Jeep lurch. At the top of the climb, I saw that the CEL was lit. Read the codes (a code reader needs to be in every Jeep on the trail) and got a P0755 2/4 Solenoid Circuit code. I figured my day was over and started to head out, but found that the transmission was in limp mode. It was driveable, but not great so I cleared the code. As I was getting close to the trailhead, it happened again. I cleared the code again, and it came back immediately. At this point, I was a couple hundred yards from pavement, and about a mile from the nearest gas station but a long way from home. So I limped there, called AAA and got towed back to the transmission shop.
This time, the shop said it seemed to be an issue with the wiring or the TCM. But they managed to get things working again after pulling the electrical connectors, cleaning them, and reseating them. So I drove home and things seemed fine, but the next time I took the Jeep out, I got about 10 blocks before it lurched again and I got the CEL and P0755 code again. So, it went right back to the transmission shop.
Other than not being able to chase down this problem, the transmission shop has been pretty good. I paid for the temperature sensor, but they haven't charged me for anything since. And when I brought the Jeep back in, they said they would swap out the transmission solenoid and not charge me until we figured out the problem. So the Jeep got a new transmission solenoid and seemed to be doing better with a few trips around town. And no charge (yet) for the additional parts or labor.
I wanted to make sure everything was good, so I took it out on an easy trail run today and it did great. The trail wasn't too hard, but had plenty of small rocks, and some good climbing and descending. And I didn't baby it. I made the Jeep work hard because I wanted to know if it was fixed.
Then, on the drive home, driving off from a stoplight that had just turned green, the Jeep lurched again and gave me the CEL and P0755 code. I pulled over and tried to clear the code, but had no luck. It just kept coming back. I was only a few miles from home, so I drove for a bit in limp mode, but I got sick of that and pulled over to clear the code again. This time it worked and I was able to drive the rest of the way home without any problems.
At this point, I'm thinking that the problems are likely in the wiring. Like a short or an intermittent open circuit. The fact that things seem to be so random has me thinking that it's not something that completely failed. Also, the fact that the problems seem to come and go when the transmission shop messes with the electrical connectors suggests it might be something there.
I am going to replace the Transmission Control Relay tomorrow, because why not? That's cheap and easy so it's no trouble if that doesn't fix things.
But I'd be interested if anyone else has suggestions, especially @Wranglerfix or @Jerry Bransford since you guys seem to have dealt with this P0755 code before.
Does anyone have any suggestions that might help?
I was out on the trail and noticed the transmission shifting notably harder than usual. No CEL, no codes that Torque could find. Everything else was fine and the Jeep was driveable, but after I got off the trail I took it in to a local transmission shop and got it checked out. They said the transmission temperature sensor was being flaky, and there was a (hidden) code in the TCM for problems with that sensor, so they swapped out the sensor. While they were in there, they gave the mechanical parts of the transmission a clean bill of health, so it seems like that stuff is in decent shape.
Not long after, I was out on a trail doing a moderately steep hill climb and noticed the Jeep lurch. At the top of the climb, I saw that the CEL was lit. Read the codes (a code reader needs to be in every Jeep on the trail) and got a P0755 2/4 Solenoid Circuit code. I figured my day was over and started to head out, but found that the transmission was in limp mode. It was driveable, but not great so I cleared the code. As I was getting close to the trailhead, it happened again. I cleared the code again, and it came back immediately. At this point, I was a couple hundred yards from pavement, and about a mile from the nearest gas station but a long way from home. So I limped there, called AAA and got towed back to the transmission shop.
This time, the shop said it seemed to be an issue with the wiring or the TCM. But they managed to get things working again after pulling the electrical connectors, cleaning them, and reseating them. So I drove home and things seemed fine, but the next time I took the Jeep out, I got about 10 blocks before it lurched again and I got the CEL and P0755 code again. So, it went right back to the transmission shop.
Other than not being able to chase down this problem, the transmission shop has been pretty good. I paid for the temperature sensor, but they haven't charged me for anything since. And when I brought the Jeep back in, they said they would swap out the transmission solenoid and not charge me until we figured out the problem. So the Jeep got a new transmission solenoid and seemed to be doing better with a few trips around town. And no charge (yet) for the additional parts or labor.
I wanted to make sure everything was good, so I took it out on an easy trail run today and it did great. The trail wasn't too hard, but had plenty of small rocks, and some good climbing and descending. And I didn't baby it. I made the Jeep work hard because I wanted to know if it was fixed.
Then, on the drive home, driving off from a stoplight that had just turned green, the Jeep lurched again and gave me the CEL and P0755 code. I pulled over and tried to clear the code, but had no luck. It just kept coming back. I was only a few miles from home, so I drove for a bit in limp mode, but I got sick of that and pulled over to clear the code again. This time it worked and I was able to drive the rest of the way home without any problems.
At this point, I'm thinking that the problems are likely in the wiring. Like a short or an intermittent open circuit. The fact that things seem to be so random has me thinking that it's not something that completely failed. Also, the fact that the problems seem to come and go when the transmission shop messes with the electrical connectors suggests it might be something there.
I am going to replace the Transmission Control Relay tomorrow, because why not? That's cheap and easy so it's no trouble if that doesn't fix things.
But I'd be interested if anyone else has suggestions, especially @Wranglerfix or @Jerry Bransford since you guys seem to have dealt with this P0755 code before.
Does anyone have any suggestions that might help?
