Hi all, so I’ve been dealing with a P0306 code for several months now and I’ve now reached the conclusion that I believe it’s a problem with the PCM and I need it either fixed or replaced. I’ve switched injectors #5 and #6 to see if the issue followed, it changed nothing, I’ve done a fuel pressure test on the line and it was good, did a compression test and it looked good, switched spark plugs 3 times, changed the coil rail, checked for vacuum leaks and checked the wiring with a test light and it was lighting up. Also changed the cam position sensor and still having the same code so I believe the PCM just needs to be repaired. If @Wranglerfix could provide some insight I would greatly appreciate it.
P0306 PCM Problem
- Thread starter aidanm
- Start date
I can test the ecm if you’d like to send it into me. We can run it in one of our jeeps and the turnaround time is 24 hours.
Faulty spark plugs or wires, Faulty coil (pack), Faulty oxygen sensor(s), Faulty fuel injector(s), Burned exhaust valve, Faulty catalytic converter(s), Stuck/blocked/leaking EGR valve / passages, Faulty camshaft position sensor or Defective computer. It could be any of the above.
Wiring too!
What troubleshooting steps have you tried?
Do you have a code reader that can read live data?
-Mac
What troubleshooting steps have you tried?
Do you have a code reader that can read live data?
-Mac
I do keep getting a p4056 code for a small evap leak, I replaced the leak detection pump so it could maybe be that
I do have a code reader that can read live data and it shows for every misfire that it’s at a low rpm, usually right around 700 rpm
After I clear the code if I’m just driving on the highway at a normal rpm then the code doesn’t come back and it runs smooth but as soon as I get into the city and am at idle a lot it starts running like crap
Spark plugs have been done multiple times and coil rail has been changed
How's your fuel pressure?
Have you tried a compression test or a leak down test?
Timing chain?
-Mac
Have you tried a compression test or a leak down test?
Timing chain?
-Mac
Fuel pressure is good, compression test was good, timing chain and gears were replaced when I put this newer motor in
I'll assume the fuel injectors are probably good...
Sounds like it's time to start ripping into your wiring harness and verifying everything.
I don't know about the 2002 but Cam and crank sensor? At what point do they need to be synced?
-Mac
Sounds like it's time to start ripping into your wiring harness and verifying everything.
I don't know about the 2002 but Cam and crank sensor? At what point do they need to be synced?
-Mac
Yes injectors have been swapped to see if the problem followed and it didn’t and I used a test light and it blinked from the connector on cylinder #6
I’m thinking about sending out my computer to you guys to get tested, any idea about how much it would cost and how long it would take to get back?
