[Bobp]

Apologies for lurking here almost 2 years and not introducing myself.
I own two Jeep Grand Cherokee WK 2005 & 2006 4.7 and various google searches kept bringing me to this forum.
Some very useful conversation here. My retirement goal was to spend lots of time in the garage working on old cars. Recently experienced both the valve drop issue and both vehicles have the "gremlins" associated with the canbus modules. Quite educational, challenging and potentially expensive. Otherwise the vehicles are sturdy and in decent shape for rustbelt cars. Thanks for the moderators for maintaining order and offering a lot of help to me and many other Jeepers who land here looking for a solution to keep these beauties running and out of the scrapyard.
Bob P
Brighton, Mi

 

[Big Blue]

Apologies for lurking here almost 2 years and not introducing myself.
I own two Jeep Grand Cherokee WK 2005 & 2006 4.7 and various google searches kept bringing me to this forum.
Some very useful conversation here. My retirement goal was to spend lots of time in the garage working on old cars. Recently experienced both the valve drop issue and both vehicles have the "gremlins" associated with the canbus modules. Quite educational, challenging and potentially expensive. Otherwise the vehicles are sturdy and in decent shape for rustbelt cars. Thanks for the moderators for maintaining order and offering a lot of help to me and many other Jeepers who land here looking for a solution to keep these beauties running and out of the scrapyard.
Bob P
Brighton, Mi

@Bobp ;

Welcome to the forum;

There are a lot of similarities between the WK & the XK, so, you should be able to find some useful information here.

Is your WK 4WD? If so, which 4WD system do you have & what's your approximate current mileage?

 

[Bobp]

Both are Quadra Drive II.
2005=130,000 in very good shape. Recent oil pan, front control arms, half shaft and fighting gremlins. Intermittent Horn and parasitic draw possible FCM/IPM. Occasional Trans over temp after 2 or 3 miles.
2006 160,000 and solid. Recent heads reworked after valve drop. Occasional P300 and recently first trans over temp at 3 miles.
Have read and learned more about the WK canbus network than I ever suspected. Great new technology in 2003. But how many of us having working laptops or cell phones after 15 years?
Too many videos on Youtube showing perfectly good Commanders and GC's going to scrap because of gremlins.
Thanks again for your help!
Bob P

 

[Camping Commando]

Welcome Bob, im also a Livingston county lurker

 

[Bobp]

Both are Quadra Drive II.
2005=130,000 in very good shape. Recent oil pan, front control arms, half shaft and fighting gremlins. Intermittent Horn and parasitic draw possible FCM/IPM. Occasional Trans over temp after 2 or 3 miles.
2006 160,000 and solid. Recent heads reworked after valve drop. Occasional P300 and recently first trans over temp at 3 miles.
Have read and learned more about the WK canbus network than I ever suspected. Great new technology in 2003. But how many of us having working laptops or cell phones after 15 years?
Too many videos on Youtube showing perfectly good Commanders and GC's going to scrap because of gremlins.
Thanks again for your help!
Bob P

UPDATE:
Drove vehicle without any DTC codes for approx 10 miles. Repeated. Put all the interior plastics back in place and thinking AOK!!!!!

Bottom Line: Swapped salvage FCM IPM and SCM. (body computer/fuse box/clockspring) No programming. All DTC's disappeared. Everything seems to work. Network feels stable after about a dozen recycles/starts.

Lessons Learned:

1. Computer Modules are not like swapping parts.
2. Replacement Modules should be given 17 seconds on. Then ignition off. Then ignition on for several minutes to allow network resets.
3. These older WK Jeeps have fewer modules of older types. (Only 27 modules and designs are 23+ years old. They are inherently unstable compared to newer.)
4. AppCar DIAG FCA became my go-to software. Spent a lot of time looking at the settings and data from each module. Clearing codes. Retesting to see if codes return. Prime example was centering the steering angle reading which is related to install of clockspring SCM. Cleared and reset most of the major modules without problem.

Cleaning grounds, checking wiring harnesses, replacing battery were all important. Swapping modules and installing them gently cleared things up.

Just wanted to update status for all others who experience similar problems.

Bob P