have a 01 ram 1500 sport 5.9L and I keep get CEL code p0442 Evap leak small. I've had a smoke test done and they didn't find any leak but recommend I replace the leak detection pump and solenoid also gas cap so I did all that and the code just keeps coming back the only thing left to replace is the vapor cannister but I'm seriously doubt that would fix it. Also my MPG sucks big time 6.5

 

Check your plenum. Bad fuel economy is a sign of it being blown. (and it probably took your o2 sensors out as well.)

Check the fill lines, and filler neck itself for rust, leaks, or bad seal.

 

the shop that did the smoke test said there was some rust in the filler neck. i check the oil often and never had to add any.

 

Well check your plenum, it's not hard.

I diagnosed a 442 on a 99 Accent as being a vent solenoid - which was unable to close off due to chunks of charcoal from the canister going through it.

 

A blown plenum wont throw a p0442 code. Manually check all the vac lines! Mine had a cracked line where the vac line goes on the throttle body. I doubt a smoke test would catch that.

 

i used a non mopar locking gas cap, should i try a mopar cap? i've seen a few post where some have replaced caps 3-4 times then get a factory cap and it fixes there p0442 problem

 

Might be worth a shot...... If the system expects a non-vented cap, and you put a vented cap on there, that is going to cause some issues.

 

well that may of fixed it that code didn't trip again but p0601 came back that code popped up after i got it back from the smoke test and i cleared the code and removed the battery connections and touched them to fully clear it just in case, but it came back maybe aweek later so i sent the pcm to a company that repair's them and they couldn't find anything wrong with it and they also said they installed it in 2 trucks to try get the code to trip but never did so they returned it to me and this is the first time that code has been back in 3 weeks. also for whatever reason my A/C blows kinda warm air intermittently then sometimes it will frezze me out very odd.

 

Check the coupler for the temp door actuator. They are notorious for cracking, and allowing the door to basically do what it wants. (its on the bottom of the heater box, just to the passenger side of the trans tunnel.)

If the code keeps coming back, just replace the PCM. Get one from a local parts store. You might pay a little more, but, if there are issues, far easier to deal with someone in person, than via email.

 

i replaced the alternator (same part number)would that cause the p0601 also seen where it it could be a bad cell in the battery?