Engine miss-opinions please

[hdfattboy2001]

Hey guys, the last week my truck has had an intermittent miss, the engine light flashes, the engine dies for a quick second and then it continues on its merry way.

I have it on a hypertech programmer in tow mode, ran the dtc test and this is what i got-


p0472-Ex. back pressure sensor ckt. low input
p0603-ICM KAM error
p0478- Ex. pressure control valve high input
p0470-Ex. back pressure sensor malfunction
p1211-ICP not controllable pressure above/below desired

Anybody have any ideas what it could be? I dont want to just start swapping parts without having a somewhat educated guess!

The truck is a 01 7.3L w/160K

[Effreem]

Well, I'm not an expert but here is what I can help with.

1) The ICP can be disconnected. When disconnected the PCM uses the stock default value. If you notice the engine changing when you disconnect it then the sensor is bad.

2) I think the EBPV sensor is able to be removed and cleaned.

3) Do you have the same problems when using a different tune? It could be a bad tune on the programmer also.

4) Those symptoms are also slightly similar to CPS or UVCH clip issues as well. Both are common problems that I recommend checking. CPS is cheap 40 bucks from International (keep your old one until its proven bad.) The UVCH clip is a 3 hour job per valve cover just to replace a part thats 25 bucks for 3 clips (yea, it breaks so often you get 3 in a kit.)

[hdfattboy2001]

hmm, Thank you for your help, i'm going to start by changing my tune, I just started running the tow tune a couple weeks ago and before that i had no problems, so hopefully thats all it is.....

Last night on my way home from work i had cruise control set at about 75mph and the truck decided to automatically shift out of overdrive for about 3 seconds, the light on the shifter came on and all, then it went back into O/D on its own, I dont know what to think about that!

It is so intermittent though, I drive about 40 miles one way to work and had no issues till about half way home, and i had no problems on the way in....

[Effreem]

hmm...I have a manual so I don't have experience with the shifting stuff but IIRC the tune can also affect the shifting of the automatics. I do recommend trying a different tune for a bit. I would start with changing tunes for at least a few days.

[hdfattboy2001]

Well I changed my tune the other night, and today on my way to work the truck shut right off while I was on the thruway, I drove about 125 miles without issue before this happened. The truck didn't restart right away after this, just crank; It had to sit a minute or 2 then it fired right up and ran fine. I know this is similar to how a CPS is because had mine go shortly after the recall and had to change it... Are the CPS's still failing often even after the recall?
Even more confusing is the truck shifting out of overdrive on its own, it has happened 2 or 3 times in the last 2 weeks, the light comes on at the shifter and everything, when it happend on the thruway the other day it went back into O/D on its own after a couple seconds, but today at a stop sign i pulled away and noticed it did it again so I manually put it back in O/D; in hindsight i should have seen if it would change back on its own but it was a knee jerk reaction I guess..... I dont think its a tranny issue, its one i had custom rebuilt and has about 50,000 on it without an issue....

Originally Posted by Effreem

Well, I'm not an expert but here is what I can help with.

1) The ICP can be disconnected. When disconnected the PCM uses the stock default value. If you notice the engine changing when you disconnect it then the sensor is bad.

2) I think the EBPV sensor is able to be removed and cleaned.

3) Do you have the same problems when using a different tune? It could be a bad tune on the programmer also.

4) Those symptoms are also slightly similar to CPS or UVCH clip issues as well. Both are common problems that I recommend checking. CPS is cheap 40 bucks from International (keep your old one until its proven bad.) The UVCH clip is a 3 hour job per valve cover just to replace a part thats 25 bucks for 3 clips (yea, it breaks so often you get 3 in a kit.)