Hello I have a 2008 Jeep Wrangler JK unlimited X with 165k miles that has a P0841 code. The A-transmission I have is a 42RLE. I’ve been troubleshooting this fault for awhile now and I can’t seem to figure out what the solution is. I checked the Trans fluid, all good. I replaced the solenoid assembly pack. Took it to AAMCO to test wiring harnesses ,connectors & relays ,checks out good. PCM was replaced twice (refurbished-verified they were good). The vehicle does not shift hard, it starts off in second gear and is able to shift through all the other gears normally. From time to time, the vehicle will start in first but then revert to staying in second when downshifting. I did notice a bead of trans oil on some of the bolts from the Trans pan. I assume that’s a small leak from around the bolts that don’t have a proper seal. I read that could be the cause of the p0841. I’m confused because the oil level checks out. Does the tranny need a certain amount of pressure to maintain in order for it to work properly? Even if it’s a small leak like this would it cause that specific DTC?
No, a minor pan leak does not cause diagnostic faults.
Follow the diagnostic procedure here:
https://www.obd-codes.com/p0841
It's on the passenger side rear of the trans behind a heat shield so the exhaust pipe won't melt the wires. It's held in by one bolt. Lube the o rings with vaseline before installing.
Did you replace the Trans Fluid Pressure Switch? O'Reilly - Power Torque Switch #TE288 - $57.99.
No I didn’t not. I assume it’s inside the tranny on top of the valve body.
I replaced the solenoid/ switch assembly 2 times. I cannot find the trans fluid pressure switch is.
Here is an update several years later, I replaced the wiring harness that deals witht the transmission in hopes of solving this pontential eletrical issue but no luck. I still have not replaced the Fluid pressure switch. I am considering of replacing it along with the Transmission Range sensor as I can recreate the issue on my own when moving slowly between gears, I did find some corrosion on the TRS connector sticking out from the transmission. Corrosion from saltwalter sitting in there. (Jeep Beach days) I suppose maybe the corrosion made its way into the connector internally? Causing some loose contact? Will Update to see if anything changes. I also forgot to mention I Replaced the TIPM with no luck either. All that lies is insdie the tranny.