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Discussion Starter · #1 ·
My 2007 5.7l Hemi is having a transmission issue that the local dealer and Star Center can't 100% figure out and I'd like some other opinions on this before they go replacing parts on my dime.

I've worked my way through this monster of thread ( jeepforum.com/forum/f67/2007-jeep-grand-cherokee-overland-stalling-problem-1147825/index32.html
), trying to see if this is the same problem I am having, but everyone there seemed to be having stalling issues at low speeds or idling and I'm not this is the same problem.

When traveling at highway speeds (60+ mph), my car will
  • randomly give a loud "thunk" as if it missed the gear or downshifted very hard,
  • shake everyone awake,
  • dash warning light will flash
  • and a beep is heard
.

After everyone asking "what the heck was that?" it will drive normally again. Recently the issue has been happening more often and I also had a full loss of power that required me to pull over and restart the car on the highway.

This mainly happens going up- or down a hill and I believe when the RPM is <2200 with the foot off the gas.

So far the dealer has(I'm transcribing off a wall of text here):
  • Error P0884
  • verified PCM software is up to date
  • inspected PCM connectors
  • inspected C104 Connectors
  • inspected wire harness & various connections
  • performed wiggle test while monitoring trans relay
  • cleaned & tightened G100&G101 ground
  • verified proper transmission to Solenoid relay
  • swapped relay for diagnostic

at this point they opened a Star Case and escalated to Jeep
  • -cleared DTC's & inducing engine coolant temp sensor DTC then road check if coolant sensor DTC is no longer present due to possible ignition voltage spike
    ->DTC remains yet still possible ignition related (inconclusive)
  1. -inspected ignition coil electrical connections
  2. -removed coils to check for burns/abnormalities ->no abnormalities
  3. -recorded & transferred data to Star

Star now thinks that the PCM is the culprit and should be replaced, but they aren't be completely sure.

I'd be thankful for every extra opinion and possible other(namely cheaper) solution.
 

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I would go with basics - compression test each cylinder and then perform a leak down test on each cylinder. This is to make sure you are getting the right amount of compression for ignition and that the valves are working/sealing correctly. Get someone that knows what they are doing especially with the leak-down test. Not many people know how to perform that test correctly - even the dealer people.

Did the Dealer mechanics find any misfires in any of the cylinders. Sometimes you can have a significant number of misfires but NOT throw a diagnostic code.
 

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Discussion Starter · #3 ·
Did the Dealer mechanics find any misfires in any of the cylinders. Sometimes you can have a significant number of misfires but NOT throw a diagnostic code.
Not that I know of. What I wrote above is pretty much what I got back from them.
 

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My 2007 5.7l Hemi is having a transmission issue that the local dealer and Star Center can't 100% figure out and I'd like some other opinions on this before they go replacing parts on my dime.

I've worked my way through this monster of thread ( jeepforum.com/forum/f67/2007-jeep-grand-cherokee-overland-stalling-problem-1147825/index32.html
), trying to see if this is the same problem I am having, but everyone there seemed to be having stalling issues at low speeds or idling and I'm not this is the same problem.

When traveling at highway speeds (60+ mph), my car will
  • randomly give a loud "thunk" as if it missed the gear or downshifted very hard,
  • shake everyone awake,
  • dash warning light will flash
  • and a beep is heard
.

After everyone asking "what the heck was that?" it will drive normally again. Recently the issue has been happening more often and I also had a full loss of power that required me to pull over and restart the car on the highway.

This mainly happens going up- or down a hill and I believe when the RPM is <2200 with the foot off the gas.

So far the dealer has(I'm transcribing off a wall of text here):
  • Error P0884
  • verified PCM software is up to date
  • inspected PCM connectors
  • inspected C104 Connectors
  • inspected wire harness & various connections
  • performed wiggle test while monitoring trans relay
  • cleaned & tightened G100&G101 ground
  • verified proper transmission to Solenoid relay
  • swapped relay for diagnostic

at this point they opened a Star Case and escalated to Jeep
  • -cleared DTC's & inducing engine coolant temp sensor DTC then road check if coolant sensor DTC is no longer present due to possible ignition voltage spike
    ->DTC remains yet still possible ignition related (inconclusive)
  1. -inspected ignition coil electrical connections
  2. -removed coils to check for burns/abnormalities ->no abnormalities
  3. -recorded & transferred data to Star

Star now thinks that the PCM is the culprit and should be replaced, but they aren't be completely sure.

I'd be thankful for every extra opinion and possible other(namely cheaper) solution.
Hi aluminium,

I'd be happy to follow up with your dealership for you if needed. Just PM our page with your VIN and let me know!

Andrea
Jeep Social Care Specialist
 

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A word of caution. Jeep Dealers are independent Companies and Jeep has no control over the mechanics technical competence or general competence. So, unless your vehicle is under warranty, I would get a second opinion from a known qualified local mechanic before I made any new parts expenditures.

I would go to a few different repair shops and ask - "when you have a really difficult diagnosis where do you send your work?". Find that person to help you.
 

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Discussion Starter · #8 ·
A word of caution. Jeep Dealers are independent Companies and Jeep has no control over the mechanics technical competence or general competence. So, unless your vehicle is under warranty, I would get a second opinion from a known qualified local mechanic before I made any new parts expenditures.

I would go to a few different repair shops and ask - "when you have a really difficult diagnosis where do you send your work?". Find that person to help you.
Thanks, I understand that. Actually I started out at a qualified local mechanic, that comes highly recommended, and he sent me to a Jeep dealership as the error was too wonky for him and he wasn't able to fully read the error code.
 

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Discussion Starter · #9 ·
Hi aluminium,

I'd be happy to follow up with your dealership for you if needed. Just PM our page with your VIN and let me know!

Andrea
Jeep Social Care Specialist
Can't send private PMs yet, as my post count is still too low on this forum. Any other way to reach out?
 

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Did you do the ignition switch recall? We had some of those odd symptoms (not the thunk and hard shifting) check engine light and a series of random codes; heater fan would turn off and tach & speedo all cycle back and forth. Engine ran normally though. All fixed by switch replacement.
 

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Discussion Starter · #11 ·
Did you do the ignition switch recall? We had some of those odd symptoms (not the thunk and hard shifting) check engine light and a series of random codes; heater fan would turn off and tach & speedo all cycle back and forth. Engine ran normally though. All fixed by switch replacement.
I have not - might be a good try though. Thanks
 

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Hi Guys,
I‘ve got exactly the same failure on my 05 Hemi...
Did you solve the problem?
I‘ve found that the voltage of the tcm says about 7V, if I stuggle on c4 connector the voltage changes from 3V to 8V.
Hoping it’s just the connector and not the pcm...
 

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How much is the PCM to replace? I'd probably do that if they're recommending it. Sometimes intermittent electronics failures can be hard to diagnose.

When was the last time your transmission was serviced? Did this problem manifest itself just recently? How long have you owned the car? Which transmission do you have?
 

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the pcm is about 500$, but i don´t know if this will fix the problem... it could also be just a faulty sensor, or a bad ground, cable, whatever...
I hope that aluminum can tell me his fix
 

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Hi Guys,
I've got exactly the same failure on my 05 Hemi...
Did you solve the problem?
I've found that the voltage of the tcm says about 7V, if I stuggle on c4 connector the voltage changes from 3V to 8V.
Hoping it's just the connector and not the pcm...
Always start diagnosing this kind of stuff with wires and connectors. I had a car that had starting problems. Told mechanics to check the wiring of the steering column, but no, as they obviously had sh*t for brains, they replaced ECU, gateway, gauge cluster (or whatchummacallit) + whatnot, only to realize in the end that the whole problem was caused by a single chafed wire, guess where... Cost: over 2000$
 

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Discussion Starter · #16 ·
the pcm is about 500$, but i don´t know if this will fix the problem... it could also be just a faulty sensor, or a bad ground, cable, whatever...
I hope that aluminum can tell me his fix
I did not switch out the PCM after all!

Honestly I was going to but wanted to wait a month for budgeting reasons and the error never occurred after I had picked the car up from the dealer. (10k miles so far)

The dealer did mention that they cleaned all connectors, made sure the cabling was secure etc. so I think what someone else mentioned here to first check if something is loose or worn is a good start!
 

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I now have created the same issue with our 2007 Jeep grand Cherokee 5.7 hemi Overland... 🙄🙄

This all began with a start up of the jeep one afternoon...put it in drive, roll forward 2 feet and felt the loud thud... drove up & around the corner & the engine begin bucking .
Brought her home and underwent a Few days of cleaning diagnostic and etc..

At this point, what was happening was the engine would start begin to come down off of the “choke “setting and immediately cut power to the PCM/ ASD on the ground circuit/signal side. This would happen about every 2 to 20 seconds.

After cleaning every ground and tearing apart The TIPM, BCM, PCM connectors,& all the harnesses apart to check for any damage, I opened the PCM to not find any visual issues put her back together and connected to the jeep temporarily without grounding of the PCM and the problem changed, or got better to what everyone else has been experiencing which is a much more intermittent problem... seemingly only happening when going into closed loop mode. (Engine at operating temp).

I will upload a couple videos to YouTube to explain but I can actually cause the “Worst of the two “ problems to happen by grounding the PCM...

I have now cleaned every single connection at the PCM.

Can someone with access to a wiring diagram send me a PM?

I am usually “that guy “ that everyone brings the difficult stuff too....so this is starting to drive me a little bonkers being it’s My wife’s vehicle, and of course, She is one of the Most “particular “ customers in the world 😅
 

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My 2007 Jeep Grand Cherokee 5.7 hemi is doing the same things. It will ding, check engine light will flash and and it will jerk and gear down, it has made my back tires screech it does it so hard, then it will go back to normal gear. It's done this multiple times before and it's done it to my mechanic as well. It will also stall out but you usually at slower speeds or stops. It will crank back up. All sensors have been changed. New coils back to old coils. Throttle body, 2 different computers. It quit doing it for 5 months but then started back up. Sometimes you can drive it without it doing it then others it won't stop. It's not safe to drive like this and definitely not dependable. Dealership can't figure it out either and act like they've never heard of it. I've tried a different TIPM box and the ESM. Nothing has corrected it. Everything is grounded well and the kickdown solenoid in the transmission has been changed. Any help is greatly appreciated.
 

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I was having a similar problem but not as bad without the clunk in the trans but I did get a mis shift feeling then it stalled no codes so I removed my SC and ran it. work for couple of trips then it happened again took it to my mechanic he had it for awhile driving it hooked up to his pc and one day he saw a glitch from the crankcase positioning sensor cheap part
It seems to fix my problem
good luck
 
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