2006 TJ 4.0 Sudden No Crank

[S.scholler]

Hi everyone, this is my first post. This forum has been the source of all the info I’ve needed to repair this thing until now. Im stumped.

I have a 2006 TJ 4.0 M/T. I drove it the other day, parked and it has never started again.

When I turn the key to start I have all the lights and radio but nothing from the starter. All the lights on the dash work accept I have no reading from the fuel or voltage gauge.

I have replaced so far. Starter, starter relay, ignition switch, bypass clutch switch, checked ignition pin & tumbler(not broken).

I checked and get no voltage down the small starter solenoid wire. I jumped the started to get it to spin the crank with the key in but won’t start.

Also put the code reader on it and it says connection error.

Is this a PCM issue? I have had someone try and start it while I wiggled every plug I could find and still nothing.
Would you get this sudden of a failure. Most everything I’ve read shows intermittent issues before complete failure.

 

[S.scholler]

Also, someone mentioned to me it might be an SKIM issue but I have always had a dumb key and I don’t see the a module for a chip key around the ignition. Here is a pic.

 

[macleanflood]

Spray some starting fluid in the intake and see if it sputters or starts briefly... that will tell you if you have spark...

Can you hear the fuel pump running when you key on? Check fuel pressure?

-Mac

 

[AdventurePig]

Hi everyone, this is my first post. This forum has been the source of all the info I’ve needed to repair this thing until now. Im stumped.

I have a 2006 TJ 4.0 M/T. I drove it the other day, parked and it has never started again.

When I turn the key to start I have all the lights and radio but nothing from the starter. All the lights on the dash work accept I have no reading from the fuel or voltage gauge.

I have replaced so far. Starter, starter relay, ignition switch, bypass clutch switch, checked ignition pin & tumbler(not broken).

I checked and get no voltage down the small starter solenoid wire. I jumped the started to get it to spin the crank with the key in but won’t start.

Also put the code reader on it and it says connection error.

Is this a PCM issue? I have had someone try and start it while I wiggled every plug I could find and still nothing.
Would you get this sudden of a failure. Most everything I’ve read shows intermittent issues before complete failure.

How about a fuse check? Position 6 for ignition and starter, right? Fuel pump fuse?

 

[S.scholler]

Spray some starting fluid in the intake and see if it sputters or starts briefly... that will tell you if you have spark...

Can you hear the fuel pump running when you key on? Check fuel pressure?

Just tried the starting fluid and no spark. I don’t hear the pump priming either. Already swapped the ASD relay with the horn thinking it might be that and still nothing.

 

[S.scholler]

All fuses look good and buzz for continuity.

 

[S.scholler]

Also, starter was jumped to perform this test with the key in the on and someone holding it in the start position.

 

[macleanflood]

Might be time to inspect the PCM connectors.

Might be a good time to see if you're getting 5v to the sensors. I've always considered that a good test of PCM health.

-Mac

 

[AdventurePig]

Just tried the starting fluid and no spark. I don’t hear the pump priming either. Already swapped the ASD relay with the horn thinking it might be that and still nothing.

So

• power but no crank
• No pump priming noise…
• New starter, relay and ignition switch
• All fuses are good
• Happened suddenly
• Power to other accessories

Hmmm…

I think i’m leaning towards PCM, too, unfortunately, but i’m no expert.

 

[hear]

I don't know if this is a PCM problem or not, but this tends to be how I've seen the computer go out. Just one day it won't start.

I keep thinking about what a diagnostic process might look like... like working backwards what are the sequence of checks that will reveal where the issue is at.

 

[hear]

I don't know if this is a PCM problem or not, but this tends to be how I've seen the computer go out. Just one day it won't start.

I keep thinking about what a diagnostic process might look like... like working backwards what are the sequence of checks that will reveal where the issue is at.

Although if form holds, this process actually already exists in the FSM somewhere.

 

[S.scholler]

Is the fact that the code reader says communication error and cannot complete a scan mean that the PCM is fried??
Thanks for all the help and great responses!!

 

[hear]

Is the fact that the code reader says communication error and cannot complete a scan mean that the PCM is fried??
Thanks for all the help and great responses!!

Not definitively. I've had that same problem on an XJ that ended up not being a computer problem (never did solve it).

(but PCM would be my guess)

 

[JKP]

It's an 06, so PCM is suspect. I seem to remember that the PCM is actually involved in activating the starter in the 05, 06. You can pull up the FSM under Resources.

Turn the key on off on off on quickly and see if the codes read out in the odo. If no codes, it will just say "done." If no response, PCM is probably dead.

Talk to Mark @Wranglerfix, he's the go to vendor for PCMs. I had to replace my 06 PCM awhile back as it would just shut off driving down the road.