SERV 4WD - Dealership Is Stumped

[jac04]

My 'SERV 4WD' light came on. No check engine light or other lights. 2021 Mojave auto with Selec-Trac.

On my first trip to the dealership (3 weeks ago), they state that they checked for DTCs and "found DTC C140A-11 ", which is a code for Transfer Case Motor Performance. The service order also states that they did all the circuit troubleshooting for the transfer case control motor and wiring. They stated that the control module was shorted to ground internally and needed to be replaced, but was out of stock.

I looked up C140A online and found some information on the diagnostic troubleshooting steps. It basically says that if the circuits pass all the tests, then the problem has to be the control module.

This morning the control module was replaced (p/n 68483376AC) and guess what? The problem is still there.

Now the dealership says they have no idea what's wrong, so they can't fix it.

They opened up a Star Case and I'm going back for the 3rd time next week, but they're only plan is to do whatever the Star Case people tell them to.

Has anyone else been through this fiasco?

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[ShadowsPapa]

STAR is the top of the line - beyond them, it goes back to engineering. What may happen is that with an official case now open, they review it and compare to other cases. The more reports they get, the better (which is why I love it when a dealership actually opens an official STAR case - it gets compared to other similar cases around the country)
There's nothing they can do short of what they've done. They can't simply start throwing parts at it or start looking at things and wiggling connections and so on - who do they charge or bill? You?
Jeep? No, they won't get paid unless they follow exact protocol. If they deviate - they eat it, and with hourly rates north of 150/hour, in some cases all but 200/hour, it's not likely they will say "we'll keep at it until we fix it". They'll toss it back to Jeep's STAR team. If STAR authorizes it - you don't eat it. If they don't - it's going to come back on you.
The good is that you have it reported and recorded - the clock is ticking, so to speak. Keep track of the exact number of hours and days they've had it, keep track of all communications and names. If things add up - and this should fall under the "not suitable for the intended purpose" of the vehicle - you can come back on 'em. It's not like this is an annoying thing that simply bugs you but the truck is still 100% useful for intended purposes. It's broken, not capable of operating as designed or for the intended purpose.

Sad, difficult, troublesome, inconvenient as heck - but they are doing exactly what they must do. Look at the time it took them to figure out a freakin' TRAILER BRAKE CONTROLLER! Weeks if not months.

 

[Lunentucker]

Don't hang around and wait on the scheduled Star case appointment.
Techs tell me that they're told to be ready at any time from opening to close.
One told me that they didn't get the call until 5 minutes before quitting time and Star guy wanted him to stay over.
Couldn't do it because he had a kid in daycare, so then it got moved out several days again. ??‍

 

[jac04]

Sad, difficult, troublesome, inconvenient as heck - but they are doing exactly what they must do.

Yeah, I know, but it's just so frustrating. If it was summer, no big deal. But, here in CT we just got hit with a snowstorm and I had to "work from home". I'm lucky that I can, but when I get back to the office I have to hear all about how the guy with the awesome Jeep can't come in to work 5 miles away because of a little snow.

As you said, I'll have to see how this goes.

Oh, and the other thing that ticks me off a little is that if I want a loaner vehicle I'd have to wait until January 27th!!!! So, I'll have to take their shuttle home and then get a ride back. I've purchased 2 new Jeeps at the place, but I guess that doesn't mean much these days.

 

[jac04]

Don't hang around and wait on the scheduled Star case appointment.
Techs tell me that they're told to be ready at any time from opening to close.

They told me that the Star people were really backed up and wouldn't be able to get to my problem for about a day. I guess I could have left it at the dealership overnight, but I really don't like doing that. It's never spent a night outside.

They got me in for Monday morning and said the tech would be able to dedicate the whole day to it if needed.

 

[Lunentucker]

Yeah. The local tech has to be ready when they call. Problem is, it could be anytime during the whole day.
So, while he's got a whole day dedicated to it, most of that's gonna be him waiting for them.

 

[ShadowsPapa]

For the lurkers -

STAR = Service Technical Assistance Resource

 

[jac04]

Thinking about this more ... The C140A code should mean the problem is 1 of 3 things; the wiring, the control module, or the transfer case control motor. The control module has already been replaced. I've got a feeling that the control motor may have either not been checked properly or passed the test for an internal short, but is still inoperable for some other reason.

Found another person on the Wrangler 4xe forum where it looks like the tech checked the T315 / T316 circuits, and once it checked OK he just replaced the control motor.

 

[jac04]

Update for those playing along at home.

Dropped the Jeep off at 7am this morning and finally got an update at 3:15pm. The Service Advisor isn't technically knowledgeable and doesn't seem to ask the Tech too many questions, but he says the Tech is working with STAR, it's on a lift with all wheels removed for diagnostics. Not good news, but at least it will stay inside the shop tonight. I wish they'd just let me talk directly to the Tech.

So frustrating ...

 

[legacy_etu]

Update for those playing along at home.

Dropped the Jeep off at 7am this morning and finally got an update at 3:15pm. The Service Advisor isn't technically knowledgeable and doesn't seem to ask the Tech too many questions, but he says the Tech is working with STAR, it's on a lift with all wheels removed for diagnostics. Not good news, but at least it will stay inside the shop tonight. I wish they'd just let me talk directly to the Tech.

So frustrating ...

I hear you. Talking the to service writer is frustrating.

I did once have a great experience with a nearby Ford dealer. They had a ipad setup for the mechanics and they facetimed me once when I had my Explorer in there. The mechanic actually took me under my truck and showed me the issue before i approved the repairs. I thought that was a great idea. It literally was like a 3 minute video call and I was confident they had found the problem after a quick chat with the actual mechanic.

 

[jac04]

Update:

The Tech working on it simply gave up yesterday. My Service Advisor stated that the Tech told him it was "over his head" and he couldn't continue.

So, now the Shop Foreman has taken ownership of working with STAR to get this resolved. Still sitting on a lift with all wheels off, so I'm thinking that the original Tech gave up on checking the wheel speed sensors.

I'm losing faith ...

 

[hjdca]

My guess is that it is the rear locker sensor on your Mojave. The rear locker sensor isusually the one that gives you trouble.

 

[ShadowsPapa]

My guess is that it is the rear locker sensor on your Mojave. The rear locker sensor isusually the one that gives you trouble.

And there is a service kit for that so they don't have to replace the whole axle assembly like was common practice a year ago.

 

[jac04]

Interesting thought. The code I have is for Transfer Case Motor Performance. I thought the locker sensor issue caused the diff lock light to flash, which I don't currently have.

Anyhow, if there is a connection between the locker sensor and the SERV 4WD light & not allowing engagement of 4WD, then I'd hope that the STAR people would know that.

 

[jac04]

Well, the Tech sent test data to STAR per their request, and STAR says that there must be a short in the wiring harness going to the transfer case. They told me that the wiring harness can't be replaced without pulling out the engine/trans/transfer case or lifting the body off the frame. So, they are examining the harness for any obvious signs of damage, and then they will start unwrapping the harness to find the fault.

So, the Mojave will be spending Christmas at the dealership.

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