2012 Grand Cherokee 3L CRD TCM location

[Adrian2012]

Hi Drover, does your manual describe the KINM and how many pins there are and how many are used and what colour the wires are? Does it also describe where the RFHM is? My online 'manual' describes the KINM as having 6 pins and four are used, however my KINM has 12 pins and 10 are used. The 'manual' also describes as the RFHM as being "behind rear of left quarter panel", where is that? I'm guessing that means rear wheel arch perhaps near taillights, but why put it there, so much extra wiring from the dash and back to the PCM? Appreciate your input. I have asked my local Jeep dealer spares if they have a VIN specific manual and they avoided the answer and said they would talk to the head mechanic about my issue and get back to me, of course they haven't. Thanks.

[drover]

Whats another name for a KINM and a RFHM as my 3 manuals don't know them, actually I have no idea either..

Have you got any new codes thrown they can certainly narrow things down a bit..

Left quarter panel would be the passenger side kick panel, the plastic bit just in front of the door ...

Jeep won't provide a link to a online manual unless you are God and even then he would have trouble.


Okay worked out the abbreviations, will have a good look later but don't hold breath for anything much as I might have to cross reference from later models for info as no wiring dia for earlier diesels..


Other than a code for the TCCM or something what is the actual problem, a full description might help... what happens when your turn the key for a start and go from there other wise we could be running around chasing shadows............. To date the best code reader other than genuine job I have seen is Alpha OBD as it reads Chrysler/Fiat codes where others will just be generic guestimates.

[Adrian2012]

Hi Drover,
Keyless Ignition Node Module [KINM] is in the dash where the start/stop button is, which can be popped out and the "key" used to start the car. The Radio Frequency Hub Module [RHFM] gets a key position signal from the KINM and if all checks are ok will send a message to the Power Distribution Centre/Totally Integrated Power Module [PDC/TIPM and in mine is also the BCM Body Control Module] to charge the coil in the start/run relay which in turn allows power to pass through and goes to the PCM to turn on the run/accessory relays in the first key position or to start the car when in the last position, and everything fires up. Original issue was the alternator burning out, then the OBD [On Board Diagnostics] reports DTC's [diagnostic trouble codes] which advise that it has lost contact with the PCM [Power Control Module/ECM/computer]. So, the PCM was blamed and has been replaced and reprogammed with no improvement to my no-start situation. All the accessories work including the radio, the power windows, the seats and so on. Tracing the issue has revealed that the PCM does not have power when it should and the PCM gets the power after the run relays which start when the TIPM gets the signal from the RFHM which gets a signal from the KINM amongst other feedback messages. The OBD connector when tested with a digital multimeter [DMM] indicates that there is a short in the CAN bus [Controller Area Network] twisted pair wiring system which could be anywhere, I can explain how that works if anyone is interested. I am trying to get a TIPM that I can test with as it seems the most likely culprit, however I would prefer to trace the wires and test that the signals are getting through. That way I can confirm where the problem actually is and not waste more money that I can't afford chasing ghosts. Sorry, long reply but I hope people may get some value from this tale too. regards Adrian

[Treebreakerbob]

Originally Posted by Adrian2012

Hi Drover,
Keyless Ignition Node Module [KINM] is in the dash where the start/stop button is, which can be popped out and the "key" used to start the car. The Radio Frequency Hub Module [RHFM] gets a key position signal from the KINM and if all checks are ok will send a message to the Power Distribution Centre/Totally Integrated Power Module [PDC/TIPM and in mine is also the BCM Body Control Module] to charge the coil in the start/run relay which in turn allows power to pass through and goes to the PCM to turn on the run/accessory relays in the first key position or to start the car when in the last position, and everything fires up. Original issue was the alternator burning out, then the OBD [On Board Diagnostics] reports DTC's [diagnostic trouble codes] which advise that it has lost contact with the PCM [Power Control Module/ECM/computer]. So, the PCM was blamed and has been replaced and reprogammed with no improvement to my no-start situation. All the accessories work including the radio, the power windows, the seats and so on. Tracing the issue has revealed that the PCM does not have power when it should and the PCM gets the power after the run relays which start when the TIPM gets the signal from the RFHM which gets a signal from the KINM amongst other feedback messages. The OBD connector when tested with a digital multimeter [DMM] indicates that there is a short in the CAN bus [Controller Area Network] twisted pair wiring system which could be anywhere, I can explain how that works if anyone is interested. I am trying to get a TIPM that I can test with as it seems the most likely culprit, however I would prefer to trace the wires and test that the signals are getting through. That way I can confirm where the problem actually is and not waste more money that I can't afford chasing ghosts. Sorry, long reply but I hope people may get some value from this tale too. regards Adrian

Hi Adrian

My MY13 burns out fuel relay points and I have been studying the wiring diagrams in my downloaded manual but as people have said they may be the WH or MY14, I don’t know. Anyway my take on this is the BCM turns on the fuel and other relays under instruction from the pcm through the start/run relay but the fuel relay pin 86 goes back to the pcm to be earthed and that’s where I think my problem is but am hesitant to parallel another relay to the existing fuel relay with pin 86 direct to earth instead of going to the pcm, leaving the existing relay coil circuit intact to fool the pcm but sending the feed through the new one direct to the pump. What could possibly go wrong?

Your problem sounds like it is in the twisted wires that the canbus uses, when your alternator failed it could have fried a loose connection for sure

If you want I can send you my wiring diagrams as I have some of them on file that refer to the power distribution and engine power circuits

I know this sounds stupid but does your fuel pump run when you turn the key to run, have someone listen at the rear passenger door

Bob

P S it’s late I am not going to proof read this, just post it

[Adrian2012]

Hi Treebreakerbob,
My fuel pump works when the ignition is on. Have you had the Jeep recall done on your fuel pump relay? Mine has had it done and they have installed a remote relay by cutting out the wires from the looms as they go into the BCM connectors and bypassing the relay in the BCM/PDC/TIPM.
My CAN bus circuit may have a short, but where is the issue? CAN bus goes to the RFHM but I can't find it for certain and the Jeep dealership admits that they also don't have a VIN-specific workshop manual. I have written to Jeep Australia Customer Complaints and await a response. I have an 8000 page workshop manual I bought online supposedly for my model however it is actually a compilation from various third party sources as the supplier cannot obtain the actual manual from Jeep. Most of the diagrams are inaccurate but have been of general help in understanding the methodology. I will try to post part of my manual soon. Thanks

[drover]

Yes, Adrian it eventually clicked when I sat down with some circuit diagrams and followed everything but on later model diesels as my manual doesn't have a diesel circuit diagram only 3.6 and 5.7 it does sound like it could be a fried wire but canbus side of things is beyond me a little bit other than poor connections...

While I followed the circuit trails on 2 other diesel circuits nothing really stood out and I think your vision of checking individual circuits might be the way, have you had a good close look at the plug on the PCM as problems have occured from the coolant overflow dumping on it.

Sorry dragging chain getting back but have had the spanners out on my old Ute.....

[Adrian2012]

Hi,
All pins and connectors are in great condition, even the TIPM PCB's look fine but a component may still be faulty. I need to check the RFHM which does have CAN connections and the KINM does not. Thanks