ICP Sensor Replacement Fixes Three Concerns

[mchan68]

Hi guys. I have a 2005 here, that the customer couldn't start it across the street. So off I go with IDS in hand, run KOEO test. P0470, P2617 and P2262 retrieved. Monitor PIDs and notice ICP psi at 276 psi and volts at 0.59 ish at KOEO, so I'm thinking WTF? Anyhow, as I crank the engine over attempting start this thing, I notice ICP climbing and IPR duty cycle max out at around 53%. After a bit of a struggle, it starts and barely runs. IPR duty cycle fluctuates between 17 to 19%. I manage to limp the truck back to the shop. I also notice EBP psi indicating 18 psi at KOEO. So, to start off, I plugged in my tester ICP at KOEO and sure enough I get 0.24 volts. Install it temporarily, and the engine runs normally with ICP steady at 580 and IPR duty cycle at 23% steady. EBP psi now reads 14.5% at KOEO too. So, after running an air management test (which passed after replacing the ICP sensor) and reprogramming the PCM to the latest and greatest life is good. Has anyone else run across this before, or is this old news to all you diesel veterans? If it isn't, I just thought I'd pass this along. It's just that this is the first time I've ever come across one where IPR duty cycle was LOWER than usual (as opposed to higher which would indicate a high pressure oil system leak).

[joshbuys]

IPR was reading lower than usual due to the ICP fault in reading higher than actual. I've come across this same issue with an ICP sensor twice before. The first one kicked my but for a bit!

[GregKneupper]

I have seen that at least a dozen times or so. First one kicked my ass also because it was very intermittent and required extensive test driving.

[Bruce Amacker]

Very common, here's some captures I put up 3 years ago of a no-start. Note the KOEO values and lack of DTCs:

 

 

 

 

[mchan68]

Very common, here's some captures I put up 3 years ago of a no-start. Note the KOEO values and lack of DTCs:

 

 

 

 

Yes, Bruce. Those readings looked almost identical to the truck in this thread. The whole point of this post was due to the fact that replacing the ICP sensor not only repaired the high pressure oil system issue, but also the EBP reading issue as well. I know that ICP and EBP share two of the three circuits, but my question is, could repairing one also have repaired the other as what apparently happened in this case? I was almost going to include an EBP sensor and tube cleaning into the quote, but evidently it wasn't necessary after the ICP replacement.

[Bruce Amacker]

The whole point of this post was due to the fact that replacing the ICP sensor not only repaired the high pressure oil system issue, but also the EBP reading issue as well. I know that ICP and EBP share two of the three circuits, but my question is, could repairing one also have repaired the other as what apparently happened in this case?

I am also completely baffled by that. I'd write it off as a programming glitch if nothing more solid comes around.....

 

[blown99]

Your biased icp high reading created a false load % calculation (your load calculation would have been much higher probably around 40% at idle), which would cause more vgt duty cycle giving you a higher ebp reading.