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I have been lurking for a little bit trying to figure out what is going on with this car. Background is:
1. Car largely sits in a garage
2. Car was running fine prior to getting parked at my home. Drove about an hour prior. Went to start it up again, and it was running really rough, like either timing was off, or it wasn't firing on all cylinders. Went to go move and it died.
3. Tried to start it up, cranking, no start.
4. Pushed it out of the way.
5. Got a scan tool and pulled the following codes. Check Engine light illuminated, and no information on interna display. Oil pressure seems ok.
A. TCM
a. P0711 - Transmission fluid temperature sensor circuit range /performance.
b. P1798 – CAN transmission control unit/instrument cluster circuit malfunction.
B. IP – Instrument Pack
a. U1261 – SCP (-) circuit failure
b. P0562 – System Low voltage
C. PHM (Passengers head restraint control module)
a. B2306 -Seat head restraint motor jammed
D. SLM
a. U1135 - Ignition state not obtained
b. U1041 – SCP vehicle speed signal - invalid or missing
E. SRS
a. B2290 – Occupant classification system state, front passenger side
b. B2691 – Driver’s safety belt buckle switch – circuit fault
c. B2692 - Passengers safety belt buckle switch – circuit fault
d. B2438 – Passengers safety belt circuit – short to ground
I then cleared the codes, and the only ones that persisted were the TCM ones. We replaced the battery with a new one, because it was 12 years old. Still doesn’t start.
I did some research, and it might be the CAN bus faulty solder joint TSB found on the Jagrepair.com?
I see you've replaced the, battery, but it will do no harm to perform a hard reset. Follow that up with attaching a battery tender.
Originally Posted by json125266
Car largely sits in a garage
Check the fuel pressure at the Schraeder valve on the fuel rail. Ignition on for a couple of seconds, then off again. Have a cloth handy, then carefully depress the valve to check if there's any pressure. Or attach a gauge if you have one.
Is the car an 8 or an R? It can make a difference.
They have a habit of going bad when you're not looking - particularly if the car is standing for periods.
If you stick your head in the boot & get an 'assistant' to work the ignition, you should be able to hear the pump run for a second or two after ignition 'on' while it primes the system.
Fuel pressure should be around 35-40 psi.
The P0711 won't inhibit start (just add it to your list )
Last edited by michaelh; 06-25-2024 at 05:00 PM.
Reason: add approx. fuel pressure + spelling. Must get a better keyboard...
^^ What he said. The 4.0 engine fuel pumps tend to die if the vehicle sits for months (and sometimes even weeks). Best to drive the car on a regular basis. They stay happier and healthier if you do....
Update: After doing everything everyone said, It looks like the fuel pump. No noise from the fuel pump in trunk, or any vibration from actuating. I checked and replaced the fuse again, nothing. put my hand on the relay related to the fuel pump and checked that it was getting 12v in ignition position 2, I can feel it clicking over.
I ended up buying a fuel pressure gage, and after I had my daughter crank the engine. No pressure registered on the gauge.
Next Step is to replace the fuel pump. Is the only way to replace it by removing the tank in the trunk? It seems very invasive.