Help request from South Italy - DCT C140A on 2009 KK Limited 2.8 Diesel

[fiat126]

Hi to everyone everyone!
I’m writing from Southern Italy and I thank you all very much in advance for any help you can give me to solve my big problem with the KK.
Let me explain my ordeal in the hope that someone can point me in the right direction:


I bought the KK, with a 110.000milage, knowing the clutch needed to be redone and that the “Service 4WD” light would go off by itself after 1-2 minutes of driving, and otherwise 2WD, 4WD and 4WD-Low all worked normally...instead if i turn on the engine and don't move the "Serv 4WD" lamp stay on and conseguently I can't switch the T-CASE in any position...like a fool I thought that was normal. But in hindsight, if I leave the vehicle in a puddle in 2WD, turn it off, and restart it, I can’t switch into 4WD.
I’ve been an idiot.

Anyhow, the fault code being displayed is C140A.
In the meantime I’ve had the clutch rebuilt and all oils changed—including the transfer case and differentials—and ever since then, instead of the “Serv 4WD” light and the C140A error disappearing after a few meters, they now only go away if I make a sharp left turn or a left-hand roundabout; if I turn right, they stay on.
The problem comes back as soon as I shut off and restart the car.

Following the workshop manual, they checked the resistance values at the connector to rule out shorts, and everything is fine.
I’ve replaced the 4WD control unit with a brand-new original one with updated firmware.
I’ve replaced the transfer-case motor with a new non-OEM unit.
And the problem remains…


Does anyone have a suggestion?
Regards, Giovanni.

 

[fiat126]

Hi to everyone everyone!
I’m writing from Southern Italy and I thank you all very much in advance for any help you can give me to solve my big problem with the KK.
Let me explain my ordeal in the hope that someone can point me in the right direction:


I bought the KK, with a 110.000milage, knowing the clutch needed to be redone and that the “Service 4WD” light would go off by itself after 1-2 minutes of driving, and otherwise 2WD, 4WD and 4WD-Low all worked normally...instead if i turn on the engine and don't move the "Serv 4WD" lamp stay on and conseguently I can't switch the T-CASE in any position...like a fool I thought that was normal. But in hindsight, if I leave the vehicle in a puddle in 2WD, turn it off, and restart it, I can’t switch into 4WD.
I’ve been an idiot.

Anyhow, the fault code being displayed is C140A.
In the meantime I’ve had the clutch rebuilt and all oils changed—including the transfer case and differentials—and ever since then, instead of the “Serv 4WD” light and the C140A error disappearing after a few meters, they now only go away if I make a sharp left turn or a left-hand roundabout; if I turn right, they stay on.
The problem comes back as soon as I shut off and restart the car.

Following the workshop manual, they checked the resistance values at the connector to rule out shorts, and everything is fine.
I’ve replaced the 4WD control unit with a brand-new original one with updated firmware.
I’ve replaced the transfer-case motor with a new non-OEM unit.
And the problem remains…


Does anyone have a suggestion?
Regards, Giovanni.

Just to add more data, I get also to following DTCs P0581 & U0255 and one time after a I washed the car I get horn signal ON until I disconnected the fuse and also too the front windshield wiper only works in LOW or HIGH; when I set it to intermittent, it makes just one sweep and then returns to the OFF position.

 

[KJowner]

KK's are much newer than my Jeep, however the 4x4 fault is probably an ABS sensor or sensor wiring problem, the system on the later KJ and KKs uses the ABS to read wheel speed and apply the brake to any wheels that loose grip.
C140A is a fault with the transfer case shifter motor, wiring or controller.
All of the faults sound like broken wires or bad connections, especially when they fix themselves when you turn one way or appear when you get them wet. Check all the plugs and connectors for loose joints and corrosion, follow the wires and check for damage. undo any earth joints, clean with a file to bright metal then reassemble with battery terminal grease to protect it.
If you have a mechanic with a good diagnostics machine get the full system looked at, it will help pinpoint the issues.

 

[fiat126]

KK's are much newer than my Jeep, however the 4x4 fault is probably an ABS sensor or sensor wiring problem, the system on the later KJ and KKs uses the ABS to read wheel speed and apply the brake to any wheels that loose grip.
C140A is a fault with the transfer case shifter motor, wiring or controller.
All of the faults sound like broken wires or bad connections, especially when they fix themselves when you turn one way or appear when you get them wet. Check all the plugs and connectors for loose joints and corrosion, follow the wires and check for damage. undo any earth joints, clean with a file to bright metal then reassemble with battery terminal grease to protect it.
If you have a mechanic with a good diagnostics machine get the full system looked at, it will help pinpoint the issues.

Thank you so much for your suggestions; I will pass them on to my mechanic.

I’m looking for the electrical schematic for the KK but haven’t been able to find it. Could someone please share it with me?

Thanks in advance!

 

[KJowner]

If you search for

Factory Service Manual Links - KK​

On here you will find someone has posted a link to the manuals.

 

[fiat126]

Hi KjOwner,

I had already found that link, but when I click on it, I get the message:
"Available for USA visitors – Sorry, this service is not available in your country."


If a good Samaritan could share a PDF, that would be a win for me. Otherwise, I'll try using a VPN.


Thanks again!