Intermittent Electrical Issues with Power Steering Loss

[thurston]

A few months ago I started having issues with electrical and the power steering on my manual 2019 JLUR. There were variations with full Christmas tree, but generally it looked like this:

1. Dash warning comes on telling me to service auto stop/start system. The little !A with the circle around it comes on and stays on.
2. A few moments later, or at the same time, the power steering turns off.

In the beginning it would happen only at low speeds, like when the auto start/stop system would be engaged. Because of this, I thought electrical issues were the root cause and the power steering going off was a side effect, especially because of the auto stop/start message.

Most of the time I could simply restart the jeep and drive away. Once in the beginning I had the dash light up like a christmas tree and jeep would not restart. All kinds of warnings flashing. Had to disconnect the battery and reconnect to get the electronics back into a normal state. Then I could just drive away.

I tried:

1. Ensure all fuses seated.
2. Replace main battery and bypass aux (okay jeep is 5 years old, that's reasonable)
3. Replace and reconnect aux.
4. Replaced green CAN BUS connector behind the dash (relatively cheap).
5. Brought it to a shop (not cheap). They could not reproduce it while driving. They did a wiring harness inspection, rerouted some hotspots but there was no damage found.

After all of that, it happened less frequently for some period of time.

Then recently started to happen more often. On vacation with jeep loaded, while driving on the beach, after offroading on BC FSRs. Sometimes just a few messages, other times full Christmas tree.

It also started happening at higher speeds, like on the highway. I can continue to drive without power steering. Pulling over and restarting the jeep doesn't always help right away, seems now I need to let the jeep cool down. Christmas tree is more common now.

I got a scanner and a security gateway bypass so I could read and clear codes. Here are codes from various failures. In many cases it seems the CAN BUS gets flooded with junk and the modules stop communicating with each other. The jeep functions fine except the power steering.

Incident Codes

I guess the pump is the root cause and it's shorting out and putting junk on the CAN BUS. But I'm not sure. I'm reluctant to replace the pump without confirmation.

I have now started to monitor live data from the power steering module, but I haven't had a fault since I started doing that. Noticed the module temperature getting up to 60 degress C and AMPs drawn spiked to 50, sometimes up to 100 when I'm more heavy on the steering. Not sure what is normal range.

So what's my next move?

1. Replace power steering pump?
2. Keep monitoring the pump live data to look for evidence of bad pump? What is the evidence?
3. Hunt for lose ground connections?

Any insight appreciated, thanks for reading!

And finally, my Jeep:

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[thurston]

Hi @JeepCares, I wonder if this is something you can help with? Maybe engineers recognize the problem or can help diagnose?

 

[JeepCares]

Hi @JeepCares, I wonder if this is something you can help with? Maybe engineers recognize the problem or can help diagnose?

Hi Adrian,

Thank you for bringing this to our attention. As we rely on the dealership for all technical support, we recommend scheduling another appointment with your local dealer to diagnosis your vehicle concerns. Once scheduled, feel free to contact our Canadian customer care team by visiting the link below.

https://www.fcacanada.ca/en/contact_us.php?brand=mopar

Blair
Jeep Cares

 

[thurston]

I think I have this solved. It's my sway bar disconnect module or wiring to the module shorting the CAN bus. I found it by waiting for the issue, then disconnecting devices from the high speed CAN bus one by one until the short immediately went away.

The rest of this post is how I got there. I hope this helps someone out. To summarize what was done previously:

* Checking fuses.
* Temporary AUX delete.
* Both batteries replaced.
* Green CAN bus connector replaced.
* Wiring inspection and rerouting. (3 hour job)
* Shop can't reproduce it so sends me home.
* Power steering pump replaced.

None of that resolved it.

Next I start really digging into CAN bus wiring diagrams for the Jeep and CAN bus diagnostics videos on YouTube. I have no prior experience with this. I learned a crap tonne. I started testing the CAN bus with a voltmeter and mapping out which devices are connected to each wire in the two connectors for the high speed bus. I got them all labelled. I tested voltages and resistance at different places.

The real breakthrough happened when I got the idea to deliberately short the two wires of the high speed CAN bus together just to see how it responds. To my shock, that reproduced the most severe version of the issue EXACTLY. I did it three times with the exact same result each time. Christmas tree, wipers going and power steering loss.

Okay so something on the CAN bus is shorting the two wires together. Leads to a christmas tree on the dash because the messages turn to junk and power steering protects itself by shutting down (annoying in itself). Heaps of codes stored all starting with U (communication).

Next I wait for the storm on the dash and power steering failure. Windshield wipers going and everything. It has to be an ongoing short, not just a quick one-time thing. This used to take months sometimes, but lately it started happening more frequently. When it finally occurred I stopped the jeep, left it running, and started unplugging devices from the high speed CAN bus to see what happens. First exhaust sensor ... no change ... next sway bar disconnect ... then storm stops immediately. Even the wipers stop. Jeep has check engine light on and reports no sway bar module. It's back to normal.

So theory then becomes it's the sway bar disconnect module, or the wiring connecting to it shorting the two wires of the CAN bus together.

Then I plug it back in and start handling the sway bar disconnect roughly. Flexing the part where the electronics are. Wiggle wires and connectors, take the connector off and put it back on. Spray water on the jeep (water runs right over it and the wiring/connector).

The jeep starts exhibiting the issue every time I turn it on. Three times I'm able to resolve it immediately by removing the sway bar disconnect from the CAN BUS. Jeep is normal again every time. Then after those three rounds, the jeep stops exhibiting the issue.

Next day I disconnect the sway bar module from the CAN bus and pull the power fuse. Take it for a two hour drive into the wilderness and have some fun with it again. No issue. I plug the sway bar disconnect back in while out there (power and CAN bus) and the issue starts up immediately. I remove it from the CAN bus and it clears up immediately. Did this routine a second time ... same result. I disconnect it again and drive home with no issue except jeep complaining the sway bar disconnect is unavailable.

So here I am, strongly convinced it's the sway bar disconnect module, or the wiring harness leading to it. Finally feeling good about my jeep again!

 

[thurston]

Here is the wiring labeling for my Jeep. These numbers are the connector numbers on "CONNECTOR STAR CAN IP C" in the "CAN C BUS SYSTEM" wiring diagram available on the forum.

 

[roaniecowpony]

Here is the wiring labeling for my Jeep. These numbers are the connector numbers on "CONNECTOR STAR CAN IP C" in the "CAN C BUS SYSTEM" wiring diagram available on the forum.

Great job of diagnosing!

Thank you for posting the connector map on the CANBUS. I hope it's never useful to me, but I may copy this to my drive.

 

[thurston]

Thanks. Note my Jeep is a manual 3.6, so automatic transmission modules aren't present. I found the colouring mostly good. The red/orange in the wiring diagram looked more brown to me on the real-life wire.

 

[Bob Burd]

Note that those connectors can be in any slot, not just that particular arrangement. The wire colors should be consistent though between jeeps.

 

[Rikail]

Salut,

J'ai eu le même problème que toi, mais dans mon cas, cela arrivait à chaque fois qu'il y avait de l'eau ou de l'humidité. J'ai subi une perte de direction assistée et tous les voyants d'avertissement se sont allumés comme un sapin de Noël.

Pour moi, le problème a finalement été résolu, non pas par un garage, après avoir dépensé plus de 1 000 euros en toutes sortes de diagnostics et de réparations, mais par mes propres moyens.

J'ai expliqué la solution en détail dans cet article : https://www.jlwranglerforums.com/forum/threads/service-shifter.24255/page-8#post-2321569 .

J'espère que cela aide !

 

[ALN]

I think I have this solved. It's my sway bar disconnect module or wiring to the module shorting the CAN bus. I found it by waiting for the issue, then disconnecting devices from the high speed CAN bus one by one until the short immediately went away.

The rest of this post is how I got there. I hope this helps someone out. To summarize what was done previously:

* Checking fuses.
* Temporary AUX delete.
* Both batteries replaced.
* Green CAN bus connector replaced.
* Wiring inspection and rerouting. (3 hour job)
* Shop can't reproduce it so sends me home.
* Power steering pump replaced.

None of that resolved it.

Next I start really digging into CAN bus wiring diagrams for the Jeep and CAN bus diagnostics videos on YouTube. I have no prior experience with this. I learned a crap tonne. I started testing the CAN bus with a voltmeter and mapping out which devices are connected to each wire in the two connectors for the high speed bus. I got them all labelled. I tested voltages and resistance at different places.

The real breakthrough happened when I got the idea to deliberately short the two wires of the high speed CAN bus together just to see how it responds. To my shock, that reproduced the most severe version of the issue EXACTLY. I did it three times with the exact same result each time. Christmas tree, wipers going and power steering loss.

Okay so something on the CAN bus is shorting the two wires together. Leads to a christmas tree on the dash because the messages turn to junk and power steering protects itself by shutting down (annoying in itself). Heaps of codes stored all starting with U (communication).

Next I wait for the storm on the dash and power steering failure. Windshield wipers going and everything. It has to be an ongoing short, not just a quick one-time thing. This used to take months sometimes, but lately it started happening more frequently. When it finally occurred I stopped the jeep, left it running, and started unplugging devices from the high speed CAN bus to see what happens. First exhaust sensor ... no change ... next sway bar disconnect ... then storm stops immediately. Even the wipers stop. Jeep has check engine light on and reports no sway bar module. It's back to normal.

So theory then becomes it's the sway bar disconnect module, or the wiring connecting to it shorting the two wires of the CAN bus together.

Then I plug it back in and start handling the sway bar disconnect roughly. Flexing the part where the electronics are. Wiggle wires and connectors, take the connector off and put it back on. Spray water on the jeep (water runs right over it and the wiring/connector).

The jeep starts exhibiting the issue every time I turn it on. Three times I'm able to resolve it immediately by removing the sway bar disconnect from the CAN BUS. Jeep is normal again every time. Then after those three rounds, the jeep stops exhibiting the issue.

Next day I disconnect the sway bar module from the CAN bus and pull the power fuse. Take it for a two hour drive into the wilderness and have some fun with it again. No issue. I plug the sway bar disconnect back in while out there (power and CAN bus) and the issue starts up immediately. I remove it from the CAN bus and it clears up immediately. Did this routine a second time ... same result. I disconnect it again and drive home with no issue except jeep complaining the sway bar disconnect is unavailable.

So here I am, strongly convinced it's the sway bar disconnect module, or the wiring harness leading to it. Finally feeling good about my jeep again!

Thank you for sharing the steps you've taken to resolve your can bus issue. I was having issue with loosing my power steering assist after service shifter error. I replaced the green can bus but it did not resolve the problem. I disconnected the Sway Bar disconnect can bus wire after reading your post, drove the jeep for about an hour with no issue so far.

 

[TEAMSLO]

Late to the party but glad you figured it out. On my JLURD I had almost exactly the same issue, also affecting 4wd (not sure how though). Happened in a rock quarry while exploring around. Had an awesome time getting out of there in 2wd and up some pretty steep hills.

Used the tazer to disable it, went to the antirock and never looked back. On my new rig, going through a build process and have the antirock waiting in my garage.

 

[ImLostAgain]

I think I have this solved. It's my sway bar disconnect module or wiring to the module shorting the CAN bus. I found it by waiting for the issue, then disconnecting devices from the high speed CAN bus one by one until the short immediately went away.

The rest of this post is how I got there. I hope this helps someone out. To summarize what was done previously:

* Checking fuses.
* Temporary AUX delete.
* Both batteries replaced.
* Green CAN bus connector replaced.
* Wiring inspection and rerouting. (3 hour job)
* Shop can't reproduce it so sends me home.
* Power steering pump replaced.

None of that resolved it.

Next I start really digging into CAN bus wiring diagrams for the Jeep and CAN bus diagnostics videos on YouTube. I have no prior experience with this. I learned a crap tonne. I started testing the CAN bus with a voltmeter and mapping out which devices are connected to each wire in the two connectors for the high speed bus. I got them all labelled. I tested voltages and resistance at different places.

The real breakthrough happened when I got the idea to deliberately short the two wires of the high speed CAN bus together just to see how it responds. To my shock, that reproduced the most severe version of the issue EXACTLY. I did it three times with the exact same result each time. Christmas tree, wipers going and power steering loss.

Okay so something on the CAN bus is shorting the two wires together. Leads to a christmas tree on the dash because the messages turn to junk and power steering protects itself by shutting down (annoying in itself). Heaps of codes stored all starting with U (communication).

Next I wait for the storm on the dash and power steering failure. Windshield wipers going and everything. It has to be an ongoing short, not just a quick one-time thing. This used to take months sometimes, but lately it started happening more frequently. When it finally occurred I stopped the jeep, left it running, and started unplugging devices from the high speed CAN bus to see what happens. First exhaust sensor ... no change ... next sway bar disconnect ... then storm stops immediately. Even the wipers stop. Jeep has check engine light on and reports no sway bar module. It's back to normal.

So theory then becomes it's the sway bar disconnect module, or the wiring connecting to it shorting the two wires of the CAN bus together.

Then I plug it back in and start handling the sway bar disconnect roughly. Flexing the part where the electronics are. Wiggle wires and connectors, take the connector off and put it back on. Spray water on the jeep (water runs right over it and the wiring/connector).

The jeep starts exhibiting the issue every time I turn it on. Three times I'm able to resolve it immediately by removing the sway bar disconnect from the CAN BUS. Jeep is normal again every time. Then after those three rounds, the jeep stops exhibiting the issue.

Next day I disconnect the sway bar module from the CAN bus and pull the power fuse. Take it for a two hour drive into the wilderness and have some fun with it again. No issue. I plug the sway bar disconnect back in while out there (power and CAN bus) and the issue starts up immediately. I remove it from the CAN bus and it clears up immediately. Did this routine a second time ... same result. I disconnect it again and drive home with no issue except jeep complaining the sway bar disconnect is unavailable.

So here I am, strongly convinced it's the sway bar disconnect module, or the wiring harness leading to it. Finally feeling good about my jeep again!

Did you get full confirmation this was the issue? Tracking down something similar...

 

[thurston]

Did you get full confirmation this was the issue? Tracking down something similar...

I ran for a while with the sway bar module removed from the CAN bus at the green connector behind the glove box and did not have an issue. I then ran with wire connected at the green connector, but detached from the sway bar module up at the front of the jeep. Problem occurred.

I asked an electrician friend to inspect the wiring in the front (it used to run under the radiator) and visually he could not find any explanation for the shorts.

Now I need to try to find problems with the wiring buried deeper, but I've taken a little break from the investigation, just running with the sway bar module disconnected.

 

[Barney392]

I ran for a while with the sway bar module removed from the CAN bus at the green connector behind the glove box and did not have an issue. I then ran with wire connected at the green connector, but detached from the sway bar module up at the front of the jeep. Problem occurred.

I asked an electrician friend to inspect the wiring in the front (it used to run under the radiator) and visually he could not find any explanation for the shorts.

Now I need to try to find problems with the wiring buried deeper, but I've taken a little break from the investigation, just running with the sway bar module disconnected.

I've heard of a number of incidences in the early years of the JL where the wiring for the sway bar disconnect would be rubbing on the radiator. It would wear through the covering and mess with the CanBus. You might try following the sway bar disconnect wiring as far as you can and look for this. Just a thought.

 

[ImLostAgain]

I ran for a while with the sway bar module removed from the CAN bus at the green connector behind the glove box and did not have an issue. I then ran with wire connected at the green connector, but detached from the sway bar module up at the front of the jeep. Problem occurred.

I asked an electrician friend to inspect the wiring in the front (it used to run under the radiator) and visually he could not find any explanation for the shorts.

Now I need to try to find problems with the wiring buried deeper, but I've taken a little break from the investigation, just running with the sway bar module disconnected.

Thank you for the follow up! It is appreciated.

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