Another observation about biased ICP

GregH · June 17, 2012

Every now and then I get another truck with concerns caused by a biased ICP sensor. Most recent one was a tow in complaining of a normal crank and start, but it will not rev up or move. When I checked it it was a crank no start. ICP is .86V, 580psi at KOEO, so of course it won't start.

However, when I turned the key on I didn't hear the injectors precycle! So, my first step was to check for codes - none. Datalogger shows VPWR and LPWR at 12V, MPWR at 48V. Cycle the key again, and still no injector precycle. Then I looked at ICP and saw the biased reading.

Once I jiggled the ICP connection, my precycle came back and the engine would start.

I don't think I'd ever seen the FICM fail to precycle the injectors when the ICP reading was off.. Interesting idiosyncrasy in the PCM calibration...

Jim Warman · June 17, 2012

Cool catch... 6.0s are getting to be almost rare around here. Looks like the next popular repair is going to be 6.7 EGR coolers????

Brad Clayton · March 17, 2013

However, when I turned the key on I didn't hear the injectors precycle! So, my first step was to check for codes - none. Datalogger shows VPWR and LPWR at 12V, MPWR at 48V. Cycle the key again, and still no injector precycle. Then I looked at ICP and saw the biased reading.

Once I jiggled the ICP connection, my precycle came back and the engine would start.

Just ran into one of these yesterday, couple of screen shots from it:

The owner had been dealing with it's driveability symptoms for 2 years and had been to multiple shops for multiple repair attempts. We called him in a pretty timely manner with a very low quote to fix it, then called him back just as quick with the news that it was fixed. He was skeptical and would not come to pick it up until we drove it again over the weekend. You can't ask for a better running vehicle and I am sure he will be quite happy with the repair.

ETS · March 23, 2013

Was ICP voltage irratic?

From previous post had 03 that had fried FICM. Ran great for a week then another list of problems. ICP voltage is constant but it varies each time I have run it. All on cold engine from .84 to 1.35. At idle. I am unable to run waveforms.

fergy12 · October 8, 2013

This is an oldie but thought id comment on my experience with one today, customer complaint of lagging on acceleration from a stop intermittently, and will have dead pedal intermittently, intermittent rough idle. Checked codes code P0299, All PIDS, ICP, EBP all appearing normal, Noticed when did occur EBP was 17-18PSI VGTDC-85% before accelerating and when it didn't lag on accel was getting 15-16psi VGTDC-75-80%. So after swapping a VGT with no change. EGR test pass, Turbo test pass. Fumbled around some more looking at pids thinking possible turbo sticking, but turbo was done a year ago... pulled out EBP looked okay but replaced anyway went to start it up and it wouldn't start. Checked ICP voltage .55V KOEO, wiggled the sensor around with no change, after about 2 minutes it dropped back to .24. So Replaced ICP sensor as well, roadtested and runs good now! Not entirely sure whether it was the EBP causing the higher EBP readings, or a bad ICP skewing VreF readings causing those erratic readings.