Jeep Wrangler Forum banner

1 - 4 of 4 Posts

·
Registered
Joined
·
593 Posts
Discussion Starter #1
Today my jeep suddenly stalled and wouldnt start back up. Fuel pump will not prime. Dash gauges do not work when key is in Run position but they do work properly when I do the self diagnostics. My code reader is unable to establish a connection with the PCM. Engine will turn, all electronics work as they should, all fuses good. Bad sensor or bad pcm?
 

·
Premium Member
Joined
·
560 Posts
Always scares me that something like this could happen out in the back country in the middle of nowhere one day.

Hope you find the problem quickly.

Sent from my SM-G973U using Tapatalk
 

·
Premium Member
Joined
·
564 Posts
May be you have a module bringing down the PCI bus or problem with the PCI bus. The SKIM module is on the PCI bus along with the instrument cluster. If the SKIM module is getting "blocked" because of issues with the PCI bus then the PCM cannot get the message to allow a start. Also if that PCI bus is not working the instrument cluster cannot get messages as to what to set gauges to.

I am not ruling out what you said, but I'd look at the bus first. Now how do you look at it? I watch a lot of youtube mechanics and have seen them troubleshoot networks and usually it involves an oscilloscope. They also will troubleshoot by see if the network looks "bad" on the scope then unplug modules on the bus to see if one module is bringing the network down. So maybe a test is to plug your scan tool in and unplug modules and attemp to communicate with the PCM (PCM being the last one you'd unplug).

Maybe others have some ideas. I just hate to wing a PCM at this when it's the SKIM, or ABS (it's on the SCI network but worth unplugging), or ABS module.
 
1 - 4 of 4 Posts
Top