Transmission won't shift out of park

[JTS]

Hey guys, new member here. I have used this forum quite a bit but haven't posted here.

Yesterday I was changing the O2 sensors and ran into a couple issues.
I have a 2005 SE 4.0L with a 42RLE.
So I changed the O2 sensors and didn't realize that I had accidentally knocked off the vacuum hose for the brake booster. So it idled higher than normal and the brake pedal got really firm. I figured the high idle was an issue with the new O2 sensors but couldn't figure out the brake issue. I tested out the brakes several times and had to press really hard to get the jeep to stop especially when it was idling high. I ended up seeing the vacuum hose off and fixed it which fixed the high Idle and the brake issues.

Now the transmission won't shift out of park when I start the Jeep. If I turn the ignition to accessory I can shift the jeep into neutral and start the jeep then put it in gear. The only thing I can think of is when I had to press the brake pedal super hard something might have happen and now a brake sensor isn't working which is keeping the shifter in park when running.

I saw the chopstick fix but if the shifter work fine when the key in in ACC, it just doesn't work properly when the engine is running. Thats what makes me think it may be something else.

Thanks guys, any help is appreciated.
Jay

 

[tr21triton]

its your neutral safety switch...

 

[JTS]

its your neutral safety switch...

The jeep starts just fine in park and in neutral. If I start it in park I can't shift it to any other gear. If I turn the key to acc I can shift it to neutral and start the jeep and shift it normally to any gear including park but I can't take it back out of park. Does it still sound like the neutral safety switch?

 

[ErikOffroad]

Dumb question do the brake lights still work

 

[JTS]

Dumb question do the brake lights still work

Not that dumb of a question. But it was dumb of me not to check to see if they are working. I'll check when I get off work.

 

[ErikOffroad]

You have to get power through the brake switch to the interlock sel. I’m wondering if the fuse for the brake lights is bad

 

[JTS]

I'll definitely check the brake lights/fuse when I get off work.

The only other thing I can think of is, when I was testing it out I drove it on my farm over some really thick brush. I don't know if the brush might have pulled a wire or something that may have caused it. I'll also crawl underneath and look around.

 

[tr21triton]

The jeep starts just fine in park and in neutral. If I start it in park I can't shift it to any other gear. If I turn the key to acc I can shift it to neutral and start the jeep and shift it normally to any gear including park but I can't take it back out of park. Does it still sound like the neutral safety switch?

as it should. but unless the brake pedal is pushed down a min. of 1/2 in it will not allow you to shift out of park or neutral

 

[ErikOffroad]

It should be fuse 10 behind the glove box

 

[tr21triton]

just checked the manual and it says you need a new transmission, it's the shift pawl thats stuck and needs a rebuild to unstick it...

 

[JTS]

So I got home and checked the brake lights and they are working fine. I checked the switch for the brake lights at the top of the brake pedal and it it working fine.

So one thing new I noticed tonight is that it actually won’t cycle through the shift positions if the key is turned forward to the point the lights and radio come on. If I rotate the key forward to the first click it doesn’t power up the accessories and I can shift the transmission out of park and into other gears. I am also able to start the engine in any gear. If I shift back into park with the engine running I can’t get it back out of park.

 

[ErikOffroad]

It could be a long shot but that fuse would have power only in the run position. I would take a test light and see that you actually have power at it in the run position. If it doesn’t or has it intermittently it could possibly point to the ignition being bad. Also you can pop the cover off over the shifter and get access down to the shifter to see e Solenoid and shifter detent to see if anything is obstructed and make sure that you have power going to it on the yellow pink wire. The wire I think it’s orange white should have a ground when the brake petal is pressed. to try and see if it is bad or eliminate that as being the problem. I really think that the ignition is the source of the problem now. But ya start at the fuse. That’s the easiest spot to test it

 

[ErikOffroad]

Also another test you can do is if you can get your fingers on the solenoid. See if it clicks, do this in the accessory position where it is currently working and compare that to the run position. See if you can feel it click

 

[ErikOffroad]

If you can report back with these tests and let me know what is going on that would be great. I still at that point would have to go through the wire diagram again to make sure that it is not possibly a bad relay before I can confirm that it is the ignition switch

 

[ErikOffroad]

I went through the digram. The power does come off the ignition switch straight to the fuse pannel. If the ignition is the problem fuse 9-12 would be affected

 

[ErikOffroad]

The only thing that I find weird though is that you can move the shifter in accessories. According to this it should only be powered in run and start

 

[ErikOffroad]

I just feel like summarizing all of this for some reason. If you go to the fuse pannel and check fuses 9 through 12 and have no power to them in the run position, then turn the ignition to accessory and see power then this part of the ignition switch that I highlighted is bad. I think this is what happened. At that point call a Jeep dealership give them the vin and get a new ignition. Problem solved.

 

[JTS]

Erik, first of all let me thank for your taking the time to help me. I know it took some effort to write all that and post pictures of the wiring diagrams.

I also would like to explain something about my key positions. I pulled out my manual and realized that I was mistakenly calling the lock position the acc position. My jeep has acc, lock, OFF, on/run and start positions. If I turn the key back its acc, then lock where I can pull out the key, then one click forward is the OFF position, another click forward is the on/run position. I may have confused everyone earlier.

In the ACC postion I cannot put the transmission into gear
In the lock position I cannot put the transmission into gear (working normally)
In the Off position I can put the transmission into gear and it will start in any gear ( I don't think it should do this)
In the on/run position I cannot put the transmission into gear

In order to get to work this morning I had to put the key in the off position, put the transmission into gear and start the jeep with my foot on the brake. Then I could shift from reverse to drive without an issue but if I put it into park I couldn't get it back into gear.

I tested all the fuses and had to push my volt meter pretty hard into the metal on the back of the fuses to get them to read voltage. I did notice that in the Off position non of the fuses 9-12 had power. In the on/run position they all had power after pushing pretty hard on them.

Now here is the weird part. After testing the fuses and confirming that they all work properly my jeep is now shifting out of park with the vehicle running in the on/run position. I can still shift the jeep into gear in the off position and start the jeep in gear and it will lunge forward as it starts. That part doesn't bother me too much but I guess that would be the neutral safety switch? I don't know if the fuses just weren't making good contact and moving them around fixed the problem but its working right now.

Thanks Jay

 

[tr21triton]

If your Jeep Wrangler has an automatic transmission, it likely has a neutral safety switch that prevents you from starting the engine while the vehicle is in gear. The neutral safety switch also often controls the reverse light switch, which activates the backup lights when you are in reverse. With time, the neutral safety switch can fail or fall out of adjustment. When this happens, your Jeep may not start, or it may only start while in Neutral, but it won't start in Park. In some cases you may also find that you can start your Wrangler in any gear, which may be dangerous and cause the vehicle to lurch forward. O'Reilly Auto Parts carries neutral safety switches for your Jeep Wrangler so you can make your repair and start your Jeep with confidence.

 

[tr21triton]

i would check the spark plug wire routing