I recently had the P1899 code. Transmission neutral/park switch stuck or in the wrong position. I replaced the switch and less than 100 miles had the same code. When I clear the code it will return randomly. If you have any suggested starting points I welcome them.

did you tighten the new switch all the way? is it supposed to have a washer on it? how many miles on the tranny the thing that it slides on could be worn

Sorry about the slow response, I thought things could not be busier. I did tighten the switch but no washer was on the switch I removed so none on the replacement. Washer did not come with the new switch either.

since it comes randomly and you think the depth is correct i would look for damaged wiring. if you are lucky your chilton will have a schematic and you can check for continuity at easy to tap in points like harnesses. otherwise you get the fun task of tracing the wires.

I wonder, do you have the performance problems associated with the code after the repair, or just the code ? See, in mine, a code for an altogether different issue was stored, and you can't clear them any more by just disconnecting the battery. I know it's stupid, but this wasn't made clear.

I never had any type of performance issues, just the light and the code. Strange thing, the switch is a dual switch. Half is the part/neutral sensor and half is the reverse sensor. The reverse section has always worked and upon inspection of the old switch, it appears to be perfectly normal. I guess I'll have to buy a scanner to monitor the switch during use. Would you agree that it has to be wiring problem or an actuator inside the transmission.

Could it be just a stored code that was never cleared ? Again, I'm not trying to be stupid. It just comes natural. Don't let me offend you with my simple questions.

i don't think it has much to do with stuff inside th transmission i think the wires or a connectors is all messed up that are going to it.

I just want to know more about this fly fishing jeep. I love Jeeps and fly fishing also. There was no vehicle info on your post. That usually helps "the boys" solve your problem.

You are right, I'll update the Jeep info.
We cleared all the codes, last time it happened again in 10 minutes and the time before it was 5 days before it happened. I'm of the same opinion that its the wiring. I've been in electronics my whole life but I sure not fond of digging into auto wiring.:( I have the full schematics, so I guess I'll have to do it sometime.

Sorry about the edits, but I wanted to ask - I've never had the skid plate off this thing. It looks like it supports the transmission. Sure would be easier to check the wiring if it was off. Any surprised in pulling the plate? Ok to drive without it for short 'on road' tests?