Ok so I have a 2002 Dodge ram 1500 slt 4.7 2wd, now before I get to the codes I'll layout what I've done to the truck since October. I pulled the motor and rebuilt it from the crank up, it has rebuilt heads all new gaskets, new timing components, new water pump, belt tensioner, thermostat, alt, battery, clutch fan, harmonic balancer, cam and crank sensors, throttle and idle sensors, new intake, etc so when I bought this truck the motor was locked up I yanked it out tore it apart rebuilt and replaced any part that was not in good shape. The pcm was bad so I went to the junk yard and pulled one from a Dakota swapped the tone rings to match this pcm. I flashed it to my vin and I've gotten about 4,500 miles on it since October. Well last week I could smell coolant so I popped the hood and I had a leak from the water pump so I went ahead and pulled everything to the timing cover replaced every seal and gasket , put a new water pump and clutch fan, thermostat etc.. started it up it drove fine but then yesterday I came home from work and when I parked it I had no DTC but this morning I started it and it sounded week starting. So I fill it up come back and I put my code reader on it and I get 6 DTCs I clear it drove it and didn't come back restart it and Bam I've got more codes. I'll list them at the bottom any thoughts or suggestions would be appreciated.


​​​​​​P0300,p0301,p0304
p0600,p0603,p0072
So I've got cylinder 1,4 misfire
Multiple cylinder misfire these were the first codes.

Keep alive memory
Serial communication link failure
Ambient air temp sensor circuit low these came on the second time but they have only came on once
​​​

 

p0603

That one makes me nervous. Basically, what its telling you is the PCM doesn't trust the learned values any more. Resetting the PCM should clear the codes, along with the keep alive memory...... but, if the code comes back, that's a failing PCM.

 

Ok so I've never reset a PCM how do I go about that?

 

Disconnect the battery. Turn on the headlights. Leave it for a minute or three. Turn off the headlights, reconnect the battery. That should cause the computer to forget everything it learned.

 

Would a bad battery cause this as well??

 

Possible. If there is a bad connection, or low voltage condition, that would likely annoy it. But, I have never seen that condition set the P0603 code....... That one is just odd......

 

Ok cleared it out and so far no codes, I did notice it started easier but I'll let you know how it does after I drive it.

 

Ok so I drove it yesterday no problems, but this morning when it was cold I had a hard time getting it started, it popped back a little almost like timing but I just did the timing in October, very hard start but once it got started it was fine, until I took my kids to school when I was accelerating it was surging for a little bit then quit. Low RPM in drive at stop it's like 500rpm. So I know some vehicles don't like aftermarket parts so I'm wondering if my TPS might be the issue. The only aftermarket parts I have are TPS, IAC and I think the camshaft sensor might be aftermarket. No codes of any kind, live data looks fine.

 

Clarify; timing is controlled by the PCM. Did you alter the timing?

 

I'll have the battery tested but I checked the battery and alternator and both were at 13-14 volts but maybe a bad cell.