Strange computer/electrical problem? - JKowners.com : Jeep Wrangler JK Forum
 
LinkBack Thread Tools Display Modes
post #1 of 19 Old 03-24-2014, 12:44 PM Thread Starter
Wheeler
 
Join Date: Jan 2009
Location: BC, Canada
Posts: 14
Feedback: 0 reviews
Strange computer/electrical problem?

I've been having some strange problems over the past month or so and wonder if it's a computer glitch, and I'm hoping somebody may have had a similar experience and knows what is causing it.

About a month ago my wife called while I was out of town and said the battery had gone dead while she was having lunch. I'm pretty sure the battery was not dead at the time. Anyway, thinking the battery was dead she got a boost and while driving home all the warning lights on the dash started flashing at random so she pulled over and shut it off. Afterward it would not start and she had it towed to our mechanic (not a dealership) and dropped off. This was Sunday. Monday morning the mechanic called and said the battery was completely dead and after they charged it the Jeep started and ran fine.

About a week ago, I had an experience where it would not shut off. I turned the key and pulled it out and the engine kept running. The first couple of times I just stalled it out. The third time I decided to let it run and see what happened, so I put it in neutral with the parking brake set, locked the doors and left it. When I came out of the store about 30 minutes later it had stopped running and that problem hasn't occurred since.

Yesterday we drove to the ski hill and parked around 10:00am. Came back at noon and started it up while we ate lunch then shut it off and left. When we came back about 90 minutes later it would not start, not even a click. The battery didn't appear to be dead as the electronics (radio, fan, etc) were all working, but when I turned the key there was absolutely nothing. I kept trying it (turn key... nothing... turn it back... repeat) and eventually it kicked over briefly. Continued trying it and eventually I got it to crank and start but died immediately. Kept at it and finally it started cranking and I got it running but it seemed like it wanted to die so I kept the throttle on and revving around 2500. We started driving home but the dash was going nuts, warning lights flashing, tach and speedo swinging wildly. Initially the temperature gauge was working but at some point it stopped. We were able to drive all the way home (about an hour) but when I shut it off it wouldn't start again. I checked the battery when I parked and it was 12.75V. This morning I went out to see if it would start and it would try but wouldn't turn over. I checked the battery again and it was down to 9.75V. There were no lights left on overnight.

This is a mostly stock '08 Rubicon Unlimited. I've changed the bumper and tied in the included marker lights using the manufacturers wiring harness and relays. Also added a winch, again using the manufacturers wiring harness. I don't think this would cause the problems I'm experiencing, and the problems didn't start when those additions were made.

I took some video of the dash behavior. You'll notice that the tach is reading 0 sometimes but the engine was always running between 2000 and 2500 rpm. Same for the speedo, we were driving between 80 and 100 km/h.

https://www.youtube.com/watch?v=OFqcIToJrAU

https://www.youtube.com/watch?v=lyvvfaMrLVQ

https://www.youtube.com/watch?v=h4KXIyqcCpo
OffTheGrid is offline  
Sponsored Links
Advertisement
 
post #2 of 19 Old 03-24-2014, 12:48 PM Thread Starter
Wheeler
 
Join Date: Jan 2009
Location: BC, Canada
Posts: 14
Feedback: 0 reviews

I forgot to mention that the electronic sway bar disconnect hasn't been working for a while (six months) and the 'sway bar' warning light flashes on the dash all the time. I pulled the fuse on it last week in case it was causing problems but doesn't appear to have made any difference.
OffTheGrid is offline  
post #3 of 19 Old 03-24-2014, 01:27 PM
JKO Addict!
 
ALASHA's Avatar
 
Join Date: Oct 2009
Location: Denver, CO
Posts: 8,226
Feedback: 0 reviews

How old is the battery?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ALASHA is offline  
Sponsored Links
Advertisement
 
post #4 of 19 Old 03-24-2014, 01:46 PM Thread Starter
Wheeler
 
Join Date: Jan 2009
Location: BC, Canada
Posts: 14
Feedback: 0 reviews

The battery is maybe a year old? It is not the original battery. When we experienced this the first time our mechanic checked out the battery, load test etc, and said it's okay.
OffTheGrid is offline  
post #5 of 19 Old 03-24-2014, 02:49 PM Thread Starter
Wheeler
 
Join Date: Jan 2009
Location: BC, Canada
Posts: 14
Feedback: 0 reviews

So after having a low battery this morning I put the charger on it and then at lunch time it fired right up like nothing had happened, with the exception that the check engine light is on. I retrieved the codes and get this:

U0168 - Lost Communication With Vehicle Security Control Module (skreem/wcm)
U110c - Lost Fuel Level Message
U0121 - Lost Communication With Anti-lock Brake Module
P0627 - Fuel Pump Control Circuit
P0481 - Cooling Fan 2 Control Circuit
P0480 - Cooling Fan 1 Control Circuit
U1110 - Lost Vehicle Speed Message
U1120 - Lost Wheel Distance Message
U110a - Lost Communication With Scm
U0141 - Lost Communication With Front Control Module
U1403 - Implausible Fuel Level Signal Received
U110e - Lost Ambient Temperature Message
U1113 - Lost A/c Pressure Message
P0571 - Brake Switch 1 Performance

Looking at this list leads me to beleive there is an intermittent problem that messes up the communication between the various control modules, but what?
OffTheGrid is offline  
post #6 of 19 Old 03-25-2014, 08:07 AM
Rock God
 
Panamon Creel's Avatar
 
Join Date: Nov 2010
Location: Central Mexico
Age: 53
Posts: 803
Feedback: 0 reviews

Maybe water go into the swaybar electronics or something got fried on the swaybar circuit board which causes CANbus communication errors therefore pull the plug on the E-Disconnect and see if this fixes your issues. FYI electric gremlins caused by the E-disconnect had been reported previously by others.


______________________________________________

2010 JKU Sahara
It's all about smiles per gallon, not miles per gallon
Panamon Creel is offline  
post #7 of 19 Old 03-25-2014, 12:57 PM Thread Starter
Wheeler
 
Join Date: Jan 2009
Location: BC, Canada
Posts: 14
Feedback: 0 reviews

The fuse for the sway bar disconnect was pulled. I wonder if it's possible that even with the fuse pulled it could cause problems and needs to have the cable disconnected at the sway bar.
OffTheGrid is offline  
post #8 of 19 Old 03-25-2014, 03:28 PM
Rock God
 
Panamon Creel's Avatar
 
Join Date: Nov 2010
Location: Central Mexico
Age: 53
Posts: 803
Feedback: 0 reviews

Yes disconnect the plug at the e-disco


______________________________________________

2010 JKU Sahara
It's all about smiles per gallon, not miles per gallon
Panamon Creel is offline  
post #9 of 19 Old 03-26-2014, 10:13 PM Thread Starter
Wheeler
 
Join Date: Jan 2009
Location: BC, Canada
Posts: 14
Feedback: 0 reviews

I reluctantly took it in to the dealership yesterday and got them to check it out hoping their diagnostic tools would provide some more definitive info. Unfortunately not. What they did determine is that the sway bar module is toast and the connector appears to have shorted out and melted inside. I suspect from water getting in there. So my plan is to disconnect the cable, remove it if possible or at least route it up somewhere dry, and convert to some other disconnect mechanism. I asked the tech to disable the sway bar module in the computer so I wouldn't have to put up with that annoying flashing light on the dash but he insisted it wasn't possible and they had never heard of doing anything like that. I'm sure I've seen posts on the forums that the dealer is able to do this. They're probably hoping I'll drop $2000 on repairs. Not likely.
OffTheGrid is offline  
post #10 of 19 Old 03-26-2014, 10:23 PM
Rock God
 
Panamon Creel's Avatar
 
Join Date: Nov 2010
Location: Central Mexico
Age: 53
Posts: 803
Feedback: 0 reviews

Yes the dealer can program the e-disco. Also programmers like the AEV Procal allow for the e-disco option to be switched on or off


______________________________________________

2010 JKU Sahara
It's all about smiles per gallon, not miles per gallon
Panamon Creel is offline  
post #11 of 19 Old 03-26-2014, 10:25 PM
Rock God
 
Join Date: May 2010
Posts: 519
Feedback: 0 reviews

I have had that exact same problem before on two other cars. Both times the ignition switch was defective. The internal contacts had come loose and the alt would disengage, but everything else would stay working. As the battery got low, the computer would freak out. Eventually, the switch failed to the point where it would take 50+ turn attempts to start or turn off the vehicle.

I replaced them both myself. One was in my XJ and the other was in my RX-7.
marcspaz is offline  
post #12 of 19 Old 03-27-2014, 08:14 AM
Rock God
 
Panamon Creel's Avatar
 
Join Date: Nov 2010
Location: Central Mexico
Age: 53
Posts: 803
Feedback: 0 reviews

Quote:
Originally Posted by marcspaz View Post
I have had that exact same problem before on two other cars.
......
I replaced them both myself. One was in my XJ and the other was in my RX-7.
You also had the swaybar disconnect light flash on your XJ and RX-7?


______________________________________________

2010 JKU Sahara
It's all about smiles per gallon, not miles per gallon
Panamon Creel is offline  
post #13 of 19 Old 03-27-2014, 10:55 AM
Rock God
 
Join Date: May 2010
Posts: 519
Feedback: 0 reviews

LOL Smartass.
marcspaz is offline  
post #14 of 19 Old 03-27-2014, 11:21 AM
Granite Guru
 
jerryn's Avatar
 
Join Date: Aug 2010
Location: South Eastern MA
Posts: 130
Feedback: 0 reviews

Looks like a short somewhere in your electrical harness causing your ECU to have issues or you have a bad ECU
jerryn is offline  
post #15 of 19 Old 03-27-2014, 01:39 PM
Rock God
 
Panamon Creel's Avatar
 
Join Date: Nov 2010
Location: Central Mexico
Age: 53
Posts: 803
Feedback: 0 reviews

Quote:
Originally Posted by marcspaz View Post
LOL Smartass.
You bet my ass is smart, those buns of steel went through all my schooling and life lessons without exceptions

The JK Rubicon e-disco is known to fail due to water in the electrical connector and with it causing electrical gremlins due to interference with the CanBus communications.


______________________________________________

2010 JKU Sahara
It's all about smiles per gallon, not miles per gallon
Panamon Creel is offline  
post #16 of 19 Old 03-27-2014, 03:16 PM
Rock God
 
Join Date: May 2010
Posts: 519
Feedback: 0 reviews

I'm guessing that is one of the reasons most Rubi owners I've seen here have replaced them. Makes since. What a crazy think to happen. You would think that it would be engineered to withstand being submerged indefinitely given what they expect people to put these through.
marcspaz is offline  
post #17 of 19 Old 03-31-2014, 11:04 PM
Wheeler
 
36Fan's Avatar
 
Join Date: Dec 2013
Posts: 67
Feedback: 0 reviews

Quote:
Originally Posted by OffTheGrid View Post
So after having a low battery this morning I put the charger on it and then at lunch time it fired right up like nothing had happened, with the exception that the check engine light is on. I retrieved the codes and get this:

U0168 - Lost Communication With Vehicle Security Control Module (skreem/wcm)
U110c - Lost Fuel Level Message
U0121 - Lost Communication With Anti-lock Brake Module
P0627 - Fuel Pump Control Circuit
P0481 - Cooling Fan 2 Control Circuit
P0480 - Cooling Fan 1 Control Circuit
U1110 - Lost Vehicle Speed Message
U1120 - Lost Wheel Distance Message
U110a - Lost Communication With Scm
U0141 - Lost Communication With Front Control Module
U1403 - Implausible Fuel Level Signal Received
U110e - Lost Ambient Temperature Message
U1113 - Lost A/c Pressure Message
P0571 - Brake Switch 1 Performance

Looking at this list leads me to beleive there is an intermittent problem that messes up the communication between the various control modules, but what?
With that many codes,I would start looking for a frayed wiring harness and or connector.
36Fan is offline  
post #18 of 19 Old 04-01-2014, 10:12 AM
Rock God
 
Panamon Creel's Avatar
 
Join Date: Nov 2010
Location: Central Mexico
Age: 53
Posts: 803
Feedback: 0 reviews

Quote:
Originally Posted by 36Fan View Post
With that many codes,I would start looking for a frayed wiring harness and or connector.
CANbus is the likely culprit with that many communication errors, in this case the e-disco shorting out the CANbus preventing various control modules from communicating.


______________________________________________

2010 JKU Sahara
It's all about smiles per gallon, not miles per gallon
Panamon Creel is offline  
post #19 of 19 Old 04-07-2014, 08:08 PM Thread Starter
Wheeler
 
Join Date: Jan 2009
Location: BC, Canada
Posts: 14
Feedback: 0 reviews

Week before last I disconnected the cable at the e-disco, covered it to keep water out, and tucked it up between the headlight and air box. I haven't had any problems since. At some point I'll buy something like a ProCal and disable the sway bar to eliminate the annoying warning light. I'm convinced all my problems were caused by water in the e-disco cable connector shorting out the can bus.
OffTheGrid is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JKowners.com : Jeep Wrangler JK Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome