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Don 'Mo Lurch'
Don 'Mo Lurch', Aftermarket & Factory Electronics
Category: Chrysler
Satisfied Customers: 504
Experience:  Cert. Chrysler Warnty, Heavy Line Mech, Mobile Electronics. Sales, Installation & Repair for 30 years
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2006 Chrysler 300 limited 3.5L(G) engine. Came to me from

Customer Question

2006 Chrysler 300 limited 3.5L(G) engine. Came to me from transmission shop who put in new flywheel and starter along with new crank sensor. Starter had gone out and ruined flywheel in process(suspect starting condition caused starter and flywheel failures) Very hard start, seems as firing out of time, but will eventually start by playing with throttle. Vehicle had P0339 intermittent crank sensor signal, an EGR code, and an ABS code C121C torque request signal denied. Cleared codes, soon as engine starts, P0339 and C121C reset. Have changed out egr valve which took care of egr code, also put new oem sensors on crank and cam. Engine will not start on crank signal alone, but will start on cam signal after 2 to 4 second delay, and runs perfect after starting as compared to when starting normally with both signals, engine will run rough for a few seconds. Have scoped cam and crank signals at rear of PCM connector(signals are good) Have gotten identical car and compared scope signals(identical). Have had 4 different rebuilt computers(from same company) programmed to car & installed.(no change) Also had identifix working with me on this vehicle, they gave up and returned any fee's charged. Have noticed when monitoring cam and crank signals and trying to start, rpm's on scanner do not show up until turning over for several seconds, and is rather erratic. Have you had any similar issues as I am experiencing, and what do you suggests for next steps?
Submitted: 3 months ago.
Category: Chrysler
Expert:  bill replied 3 months ago.

i would pull the transmission out and look at teh flexplate that was installed, and where it was purchased from, also look to be sure the wiring didn't get pinched between the engine and transmission, look for dents in the flexplate as well, you DID check the wiring with a good meter for shorts right?

Customer: replied 3 months ago.
As I stated, signals are good to pcm connector, and are identical to another vehicle with same year and identical engine. No wiring pinched, all wires to sensors tested for shorts to power and ground, signal wires tested for continuity and a 2 amp loans. Same part number of flywheel compared to OEM flywheel, plus if problems with flywheel or wiring, should show up in scope pattern comparison of other vehicle, only other variable is there is a code C121C that sets in ABS module for torque denied.
Customer: replied 3 months ago.
Let me know if you received response
Expert:  bill replied 3 months ago.

if this thing ran before the flexplate was replaced AND doesn't now that only leaves what the other shop did, the C121C will ALWAYS show when there is a critical sensor failure so ignore it, the PRIMARY code to troubleshoot is the P0339 if it has trouble with the crank sensor plugged in then that leaves the flex plate and a possible ding or the wrong one.

you need to look at that flexplate, i had a tech slightly ding a flexplate on a pacifica one time and it would not run with teh crank sensor plugged in and the patterns were fine, i was foreman at the time and it was my job to figure out what the tech did, i had him pull the tranny and there was a ding

Customer: replied 3 months ago.
This engine only starts hard, with code P0339 setting, otherwise runs perfect with good power, idles smoothly in or out of gear, customer was experiencing the hard starting before the starter & flexplate failed, which was probably caused from the mis-firing during starting. Also if you leave the crank sensor unplugged during starti and just use the cam sensor, the h will not sh
Customer: replied 3 months ago.
The transmission will not shift into overdrive if crank sensor is not plugged in during starting, even though sensor is plugged back in after engine starts, that is the only side affect that I am aware of if engine started with only cam sensor. I guess I have a hard time believing that there would be no signal differece with a damaged or wrong flywheel, since that is the signal the pcm uses for fuel and spark, but there has to be something causing this issue.
Expert:  bill replied 3 months ago.

as you can see the pcm is able to start the engine without the crank sensor, on this system the pcm uses the crank sensor for determining #1 cylinder position, and the cam for the remaining functions, hence it runs without a crank sensor plugged in, now i need to know the entire story to be of any valuable assistance, why was the flexplate replaced?

were there any crank codes PRIOR to the work the other shop did?

what's the history on the car with your shop AND the prior shop

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