[usandthe4pups]

Hey all,
I have a 2010 JKU Rubicon. Last month is when my problems started. While running around town I stopped for gas. When I went to start the Jeep, I got nothing. No clicks, no noise at all. I popped the hood and found my negative cable was a little loose. I tightened it and the Jeep fired. A few days later it did it again. Again, I checked the battery connections and tapped on the starter. She finally fired. I replaced the starter, and all has been well until today. After a 30-minute drive I shut the Jeep off. When I went to start it, nothing. Just for the heck of it I tried using the remote start and it fired up. When I got home, I shut the Jeep off and tried to start it...nothing. Again, I tried the remote start and it fired up. Where to go next? Ignition switch maybe? This only seems to happen after everything under the hood gets to running temps so maybe the ECM is failing? What say you?
Thanks in advance!

 

[johncanfield]

Welcome and howdy! I think you have proven the starter and associated wiring is functional and I like your guess about the ignition switch. Hopefully we'll get some better qualified opinions. We have a professional Jeep wrench on the forum, hopefully he'll chime in.

 

[rlenglish]

Hello and welcome.
I doubt you have a ecm problem. Make sure your battery connections are clean. Pull the clamps off and clean them.
If it is a fact that the remote start works and the key start doesn't. Keeping in mind that may be a coincident.
You have shown that the starter and relay etc. is good because it will remote start. The culprit will be in the ignition switch or security communication. Your ignition cylinder works a switch located on the back of the cylinder and you could check it with a test light. If you are able I can get you the information to help you out.
Sometimes inside the cylinder the end will break or it will get worn so bad that turning the key wont activate the switch. Does your key feel alright when turning?

 

[usandthe4pups]

The key feels good. I don't have many keys on the key chain so weight shouldn't be an issue. The battery is brand new and both fittings were cleaned while installing them. Then I replaced the negative terminal because no matter how hard I tightened it; it was still able to be moved. With the new terminal it doesn't move any longer. Other things that might be of interest are, The Jeep has 125k on it and I have recently replaced the alternator. (Before the ignition problem). Also, I do have another ignition switch arriving tomorrow. Also, when I turn the key, everything on the dash lights up normally but the engine won't turn over.

 

[WeimWagon]

The old switch and the new one...

 

[RICKSTER]

The key feels good. I don't have many keys on the key chain so weight shouldn't be an issue. The battery is brand new and both fittings were cleaned while installing them. Then I replaced the negative terminal because no matter how hard I tightened it; it was still able to be moved. With the new terminal it doesn't move any longer. Other things that might be of interest are, The Jeep has 125k on it and I have recently replaced the alternator. (Before the ignition problem). Also, I do have another ignition switch arriving tomorrow. Also, when I turn the key, everything on the dash lights up normally but the engine won't turn over.

1. replace the battery in your key. 2. with the key in the ignition but all the way to the rear "off" then turn the key forward 3 times but on the 3rd time stop in the run position, look at the odometer it will show you A code right it down then google it you might find your problem there.

 

[usandthe4pups]

I did replace the switch and that didn't help. I have noticed that when the key is in the ignition and the door is open that I only get the chime when the key is pressed all the way in. If I put the key in the ignition there is no sound. If I press the key all the way in, I get the chime. While on an overlanding trip this weekend I was constantly trying to figure it out and thought maybe the key was at fault. When I got home, I tried my spare key, but it did the same thing.

 

[usandthe4pups]

1. replace the battery in your key. 2. with the key in the ignition but all the way to the rear "off" then turn the key forward 3 times but on the 3rd time stop in the run position, look at the odometer it will show you A code right it down then google it you might find your problem there.

I tried turning the key in the ignition three times. It didn't give me any codes...

 

[rlenglish]

Some times wear or damage in the cylinder itself can be a problem. when it acts up plug in your old switch and turn it with a screwdriver.
you said that remote start works fine when it acts up? Then when you enter the vehicle you can put your key to run and away you go? If so then the pcm/ tipm is not getting a crank signal from the switch.
To test your switch when it is acting up you need power, ground and a start signal.

1	Z914	BK	22	GROUND
2	G20	VT/BR	22	IGNITION SWITCH SENSE
3	F20	PK/WT	22	IGNITION RUN/START CONTROL OUTPUT
4	N0	NA	0	NO CONNECT
5	A106	LB/RD	20	FUSED B(+)

If this checks out then it could be a WCM issue but unlikely if you can drive it after a remote start.
The power wire is fused from the tipm (fuse box under hood) and the start signal goes there also.
Let us know how you make out.

 

[Norminator]

I’ll be going into fetal position now.

 

[usandthe4pups]

Some times wear or damage in the cylinder itself can be a problem. when it acts up plug in your old switch and turn it with a screwdriver.
you said that remote start works fine when it acts up? Then when you enter the vehicle you can put your key to run and away you go? If so then the pcm/ tipm is not getting a crank signal from the switch.
To test your switch when it is acting up you need power, ground and a start signal.

1	Z914	BK	22	GROUND
2	G20	VT/BR	22	IGNITION SWITCH SENSE
3	F20	PK/WT	22	IGNITION RUN/START CONTROL OUTPUT
4	N0	NA	0	NO CONNECT
5	A106	LB/RD	20	FUSED B(+)

If this checks out then it could be a WCM issue but unlikely if you can drive it after a remote start.
The power wire is fused from the tipm (fuse box under hood) and the start signal goes there also.
Let us know how you make out.

I will check this soon, Thank you.
The thing that doesn't make sense is that when the Jeep is cold it will start every time. Its only when the Jeep has been driven for a while that it acts up. Yesterday, I started the Jeep, drove about 40 miles, turned off the jeep to get gas and it started with no problem. I moved away from the pump, turned off the jeep and went into the store. Came out and the Jeep started. I drove another 90 miles, stopped for gas, went to start it and nothing. This weekend, I thought that if I left the key in the ignition while it was off that it would start. But this turned out not to be the case.

 

[rlenglish]

Heat soaks can do strange things.

 

[Blue Baby Sound]

Then I replaced the negative terminal because no matter how hard I tightened it; it was still able to be moved. With the new terminal it doesn't move any longer.

The posts are tapered, and the terminals need to be fully seated on the posts. Can't tell you how many times I've seen this (for myself and others)
I use a large socket and mallet and gently tap them down until they are at the bottom of the posts.

IMO make sure both + and - are fully seated before troubleshooting further.

 

[usandthe4pups]

The posts are tapered, and the terminals need to be fully seated on the posts. Can't tell you how many times I've seen this (for myself and others)
I use a large socket and mallet and gently tap them down until they are at the bottom of the posts.

IMO make sure both + and - are fully seated before troubleshooting further.

I have replaced the negative terminal because I couldn't get it as tight as it needed to be. The positive terminal is fine. When I replaced the battery a couple months ago , I cleaned each terminal.

 

[usandthe4pups]

Ok, I don't know what I did but the Jeeps been behaving itself lately. I swapped the starter relay with another relay inside the fuse block about a week ago and it seems to be ok now. It doesn't make sense that the relay was the problem as the same relay is activated by both the ignition switch and the remote start system. The pins on both relays were clean and showed no signs of corrosion.