Hi Ya!
Just picked up an 03' 2500 Quad 4WD Hemi 80K. CEL was on and checked the code before I bought it, po357 Ign. coil G primary/secondary circuit failure is the code. Figured replace the coil, no problem. Removed #7 coil which was rusty and cracked, installed a new one, cleared the code with scanner, code reappeared right away. Suspected new coil was defective and swapped with #1. Same result. Inspected the #7 coil plug and wires (did not test yet) and they look free of corrosion. Any techs out there can give me some wisdom.
Thanks!

 

Check the coil primary wires for a signal while it's running. Also did you pull the #7 plugs to see what they look like?

 

Thanks for the reply. Pulled the plugs and they were clean but changed them anyway, then checked the wires while running at the connector and getting a signal, bouncing a bit from 12-13V+. By the way, it's idling very smooth with no miss. Code continues to reappear after battery disconnect and scanner code erase. Possible loose ground somewhere? Any thoughts where to go from here?
Thanks!

 

You running a tuner that advances timing?

 

Hammer- I see where you are going with this. Tuner will advance timing throwing off spark to cyl. #7? I don't know if the previous owner reprogrammed with a tuner on the truck. I cannot reach him. I did do a search under the dash and hood for a performance chip but do not see one. If this is the case would a long term battery disconnect reset the PCM to factory settings?
Thanks again!

 

Update! Been driving and more codes came up, po353, po300 as well as oruginal po357. Have alldata troubleshooting procedure, found ground in ECU is bad. Going to replace the ECU. Anybody know if ECU is plug and play or will I need a program at dealer.
Thanks!

 

IDK if it is PnP but it is good you found the issue.

 

Took a while but found I have a bad ground on the board in my ECM. Confirmed it at my local tech. I want to replace the ECM with a used one ($150) and have it programmed by the local dealer if needed who said he will not do it.... and I have to replace it with a new one ($650). Hogwash!!! the guy is on commission and wants to sell me a new part. A simple question then...anybody know if I install a used ECM with same part # will it jive with the vehicle?

 

you will need to have an ecu programmed with your trucks mileage and VIN #. when mine in my durango died, i bought a refurb from solopcms.com and they programmed it, and sent it to me.