DTCM Access/Back Wall Panel Removal…help

[Maximus Gladius]

(21 JTR 3.6, 131k kms) I’m thinking I have a locker communication issue (locker sensors have been potted in 21, they work) that all indicators (off road pages, dash locker symbol) shows lockers engaged when they clearly aren’t.

Was reading on here, that a Mojave owner experienced a communication issue for his/her locker that was linked to the DTCM (drivetrain control module) and that repair showed corrosion at the DTCM connectors.

I’ve had the leaky rear window before and did the 7mm silicone vacuum hose fix, but… made me think corrosion at the DTCM could be a viable reason for my locker issue.

So, here we are with today’s task of taking off the rear panel and I’ve got it all pulled away and flapping except for the very top clips. I ended up cracking the panel in a couple places so that made me feel like a full fledged tech attempting this task.

How do I get the top row to let go without becoming the HULK and just tearing the thing out?!

edit: I should add one more thing, yesterday was driving home with music playing and came to a light and engine shut off, hit the ESS cancel button and a loud speaker POP sound came from behind me. I turned on ESS and drove to the next light, engine shut off, I hit the ESS cancel button and again, loud speaker pop sound, ok… did a little test and turned the volume down to 0 and went to the next red light, engine shut off, hit the button and no pop sound. Hmmmmmm made me think resistance issue??? DTCM issue???

Sponsored

 

[fourfa]

There are 4-5 risers or 'towers' from the rear panel to the mating holes in the rear bulkhead. I think I broke 3 of them off completely. I could not find a way other than hulking out and breaking some.

I assume the rear seats are completely out? If you can sneak an arm up under the panel with a trim panel fork tool, some extra prying pressure from behind might help

 

[Maximus Gladius]

You’d b

There are 4-5 risers or 'towers' from the rear panel to the mating holes in the rear bulkhead. I think I broke 3 of them off completely. I could not find a way other than hulking out and breaking some.

I assume the rear seats are completely out? If you can sneak an arm up under the panel with a trim panel fork tool, some extra prying pressure from behind might help

Yup, you’re right and the seats are out too. Got a hook tool to slide up along side of the pins and tugged straight out. Snapped them all and broke the panel in another place. Oh well, there’s upgrades for that panel that are ALUMINUM!

 

[Maximus Gladius]

I’ll keep updating as I go here….
Water drips and flow down the wall is evident in the dust on the wall. Drips landed on the woofer and ran down behind the woofer. INTERESTING

 

[Maximus Gladius]

Removed Woofer and…..

 

[fourfa]

hm, not good

 

[Maximus Gladius]

I didn’t see any pin corrosion but cleaned the pins, and sprayed them with it DeoxIT D5. Taped a poly shield on it in case there’s future drips.

 

[Maximus Gladius]

Woofer seen lots of drips on the case. Woofer itself was fine.

 

[Maximus Gladius]

I’ve not had any window leak since installing the 7mm silicone vacuum line around the glass but… it’s very possible water was getting in from the cap seal. The cap screws were loose so they got a quarter turn tighter

 

[Maximus Gladius]

Asked Ai what both these modules are that are directly behind the sub woofer and to the side of the woofer. Ai is saying the module right behind is the alpine system module and the one to the side is the DTCM.

The drips don’t show making contact with the DTCM but as you see above in my other photos, the alpine module was getting dripped on.

I did take the connectors out of the DTCM and cleaned them off and gave them some DeoxIT. Now I put it together and hook up the diagnostic tool and reset it.

 

[Maximus Gladius]

So, nothing changed except I have a blue screen showing no Off Road pages. Waiting for that to become normal again. I still hear the POP noise at the back as I described above. I took out the blue tooth speaker and the noise isn’t coming from there so maybe from the woofer or the two modules.

Lockers still disengage quickly but dash indicator flashes like lockers are trying to disengage. Flashing does stop after a min or so, I guess I’m going in to the back diff now and see if oil got into that connector.

 

[WILDHOBO]

Removed Woofer and…..

Looking like you’re on to something.

 

[Maximus Gladius]

Blue screen finally let me have the red screen with Off Road pages. I figured it needed a few hours to figure things out. Still don’t have back up camera but I will by morning.

Got back into the rear diff and pulled the locker sensor and disconnected the connector. There was oil in it and the red tab wasn’t locked in place so maybe got loose and oil got in. I used electronics spray cleaned it out and finished it off with DeoxIT then reconnected it. While I was there, I undid the sensor actuator on the outside of the rear and it looked dirty so sprayed those pins out and clipped it back on.

Diff cover on and filled up and went for a drive then came up the alley and worked through the lockers. 4H rear locker, everything works likes it should and dash reads normal. 4L, rear locker works like it should. Front and back, only problem is the dash indicator takes about 15 seconds now to stop flashing.

I think I’ve narrowed down the problem to the front. I’ve got one more thing I can do and that is disconnecting the actuator connector on the outside and clean it to see if that’s been my issue. Last option is to just get the bypass harness for the front.

 

[Maximus Gladius]

Cleaned the actuator connector today and the locker issues finally cleared!

 

[Maximus Gladius]

The locker communication glitch wasn’t the diff sensors nor packed up sensor magnet with filings, it was a culmination of oil ingress in the sensor connectors in both diffs, dirty actuator connectors on the outside of both diffs and doing a maintenance electrical spray cleaning of the 3 connectors to the DTCM (drivetrain control module) located at the back wall, just to the side of the sub woofer.

All the connectors played a part in confusing the dash and Off Road Pages (drivetrain page) to recognize the lockers had been disengaged but the page showed they were locked and the dash locker signal just kept blinking like it was trying to disengage but couldn’t.

At this point most everyone would blame failed sensors or it would be a trip to the dealership and who knows what they would come up with.

I had potted mine back in 2021 so I knew it wasn’t the sensors and because my annual diff oil change includes taking off the diff covers to clean off the magnet, these guys were very clean, and I also knew it wasn’t mechanical and oil analysis shows very little wear metals which are trending down so I was left with connector issues and opened them all up and cleaned them out with electrical spray clean, followed up with DeoxIT D5 for the interior diff connectors and the DTCM connectors.

The exterior diff actuator connectors got the same spray treatments but finished off with DeoxIT Sn5 Shield which protects against moisture, salt and other exterior contamination.

This only cost me my time, oil to do the diffs again and some spray cleaning and a cracked back panel to get to the DTCM. (Upgrade time for something aluminum!) Had I just given up at the start and just installed the Z bypass harness, it would have cost me over $600 cad with shipping, exchange and customs taxes.

Sponsored