07 being really really wierd. ICP issues.

vanderchevy18 · Mar 15, 2014

OK. I have finally decided to quit pulling my hair and ask for help.

07 King Ranch ccsb 4x4. Studs, Egr delete, 4" exhaust, coolant filter, atlas 40 Ficm tune, SCT livewire with Gearhead tuning, new oil cooler, elc coolant, and fresh T6 oil change. (Issue started before Ficm tune or custom tuning)

The truck runs flawlessly in every aspect except icp sensor. When you start the truck everything is good. Once you start going though, the truck takes off, ICP spikes and then defaults to 870psi@26% DC. Every time. Start it and it initially runs good but after a couple feet of driving it freaks out. ICP sensor signal range performance code is thrown. It will also do it in park just revving the motor a couple times.

Things we have done
Checked continuity in the wires - good
Replaced ICP pigtail - no change
Replaced ICP sensor 4 times - no change
Overlaid the ICP sensor signal wire - no change
Replaced the pcm with both an 03 and an 06 pcm both being good - no bueno
Checked pcm plug and even bent the prong down a hair to ensure good connection - nothing
Looked at all the other sensors and they all read properly.
Vref-5.01
Signal return while sensor is not plugged in- .03v
Sensor wire while not plugged in - .03v
Signal return while plugged in - .02v
Sensor wire while plugged in - .27v (engine off)
Sensor wire while idling before it goes nuts - 1.05-1.08v (700-730psi) IPR 14.14% DC
Sensor wire at idle after issue starts - 1.56-1.57v (870.2 psi) IPR 32% DC

Anybody got anything that might help?

ghohouston · Mar 15, 2014

Duty cycle seems to jump quite a bit once the sensor freaks out, without much voltage or psi change. Have you pulled the ipr and inspected the screen? I've never dealt with an issue quite like yours, but that dc jumped out at me, I could be wrong though

vanderchevy18 · Mar 15, 2014

Actually no I haven't. I was going to but I can manually (from scanner) move the IPR anywhere I want it to and it seems to track and operate fine. I just kind of swept that thought under the rug.

vanderchevy18 · Mar 15, 2014

Also, the psi change when it defaults can't be trusted. It's a default psi.

Cold Roller · Mar 15, 2014

It could be something completely different, but here is my thinking for it being the IPR.

Remember the IPR is commanded, not actual. The IPR commanded when your vehicle was idling should have killed it, but it didn't. So it was trying to reduce the ICP by lowering the IPR duty-cycle, but it ran out of DC to fix the idle. Even if the screen was good, it may be the solenoid. If you used a 2-way diagnostic tool to move the IPR, you should have been monitoring the ICP and RPM since in Park, the major change would be RPM. Under load you should see larger ICP changes as power is built.

vanderchevy18 · Mar 15, 2014

It did idle down when commanded to 10% and idled up and rough when commanded to 40%.

vanderchevy18 · Mar 15, 2014

I guess we'll probably swap the IPR here in a couple days. It's at least an idea anyway.

djberg · Mar 15, 2014

i donno if you have a ipr socket yet, but if not when i did mine, after a few failed attempts, at diying one, auto zone has a 35mm deep that worked for me, but mine is an 04 late so im not 100% sure the ipr "nut" size is the same. though you will want to cut a bunch off both ends so you can get a swivel in there as well. but the one thing i dont know is where that cross over is in the back of those 03 intakes, may be a pain while attempting from the top(after a quick look from below i was not about to attempt that, though i have heard of guys doing it from the bottom with a stubby style wrench)..