So has anyones ICP sensor been proven bad but i was not leaking oil?
The symptoms of my truck sound similar to a bad ICP...fluctuating idle, surging, stalling, but it does run and start. IT tends to start acting up when it hits operating temp.
I have an 04 and the ICP sensor is in the easy spot to get to on the valve cover vs under the turbo (thats awesome) so its an easy swap. but juat wondering if there is any way to test it over simply swapping it.
I do not have a monitoor yet but a dongle is on order and will get the torqueapp for my tablet.

 

If you unplug it, the truck should crank and run using a default value. A short easy drive with no surging or stalling would confirm a issue with the sensor. Inspect the plug and wiring carefully, they can cause issues also and disturbing them could "fool" you into thinking the sensor was the issue.

 

If its flooded with oil, replace the sensor and pigtail.

 

Mine is clean as a whistle inside. BUT the symptoms point at it. Just wondering if "its happened" that it didnt leak but was still "bad"

 

It's possible they can fail without leaking. The best way to diagnose it, in my opinion, would be to hook a scangauge or similar diagnostic tool to it and watch the ICP reading. If it fluctuates at idle, especially when its surging, that would point to the ICP sensor. another way to test the ICP sensor is to check the voltage. It should be around 0.23-0.26 volts with KOEO.

 

do ya just stick yer multimeter probes down into the top of the plug to make contact with the metal in the plug? while the ICP connector is hooked up I would figure also. There is 3 wires feeding it, any advice on which 2 wires to probe?
I do have a digital multimeter so its possible for me to do just not sure which 2 of the 3 wires to check but can check them all and all combinations of same I guess

 

The voltage mentioned is the output voltage of the sensor as read by a monitor device or the pcm. Not any input voltage of the wireing.

 

10-4 dannyboy950

 

I'm watching this thread closely... my 04 is doing the same exact thing. Surging at idle and seems to be driven by the A/C clutch, well until the other day. I turned off A/C and it still did it, before that seemed to make it stop when I turned it off.

Here is the other thing I noticed, used Forscan recently on the truck (my new toy) and its showing ICP pressures above 4000 but scan gauge is only going to 2000, it never goes above 2000 and I've been watching that number for some time. Now this thread...leads me to think the same thing here and is starting to make sense.

I guess the real test would be to unplug the sensor for a couple days and watch for surging. It would be using the default numbers and not inducing a faulty one I would think. It will set a code and a light after a period of time.

 

How long can ya drive with the ICP sensor unplugged?
What are the risks to the motor having it uplugged?
This would be handy information to know should one be out on the road and this happens. Assuming its not spewing 3000psi oil all over the place...that'd be bad and stopping would be best

 

No real risks with unplugging it. The fixed default value is around 2,000psi IIRC, seeing that consistently with a monitor might indicate a open condition in the ICP wiring. It may be over fueling a bit at low RPM and mileage may be poor. At higher RPM it would be the opposite. I have the wire colors and volts=psi values at home. And of the three is vRev from the PCM and should be steady at around 5vDC. Here's the troubleshooting checklist from the manual.

ICP Testing


ICP voltage of .25 is well within the range of .15 and .35 on a hot engine koeo
Here they go changing the range...

Q: Injection Control Pressure (ICP) Sensor
Q: Introduction

Q1 PRELIMINARY DIAGNOSIS
Perform a visual inspection.
Connect the scan tool.
Retrieve and record all DTCs.
Record freeze frame data.
Clear all DTCs.
Perform the Key On Engine Off Self-Test.
Are any DTCs retrieved?
Yes No For DTC P2285, GO to Q2 .

For DTC P2286, GO to Q6 .

For DTC P2287 only, GO to Q13 . GO to Q12 .
Q2 DIAGNOSTIC TROUBLE CODE (DTC) P2285
Note: DTC P2285 indicates the injector control signal circuit out of range low was detected during the KOEO Self-Test or during continuous diagnostic monitoring.
Possible causes:
ICP signal circuit open
ICP disconnected
ICP signal circuit shorted to ground
VREF circuit open
biased ICP sensor
ICP sensor
PCM
Key off.
Disconnect the ICP sensor.
Key on.
Measure the voltage between the ICP sensor VREF circuit pin B, harness side and ground.
Is the voltage between 4.5 and 5.5 volts?
Yes No GO to Q3 . GO to Q10 .
Q3 CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND
Key off.
Disconnect the PCM.
Measure the resistance between ICP sensor signal circuit pin C, harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes No GO to Q4 . REPAIR the circuit.
Q4 CHECK THE SIGNAL CIRCUIT FOR AN OPEN
Measure the resistance between the ICP sensor signal circuit pin C, harness side and the PCM engine connector pin 29, harness side.
Is the resistance less than 5 ohms?
Yes No GO to Q5 . REPAIR the circuit.
Q5 CHECK THE ICP SENSOR
Note: This step may set DTC P2286.
Reconnect the PCM.
Key on, engine off.
Access the ICP PID.
Connect a 5A fused jumper between the ICP sensor signal circuit pin C, harness side and the ICP sensor VREF circuit pin B, harness side.
Is the ICP PID voltage reading approximately 4.0 to 5.5 volts?
Yes No INSTALL a new ICP sensor. INSTALL a new PCM.
Q6 DIAGNOSTIC TROUBLE CODE (DTC) P2286
Possible causes:
signal circuit shorted to power
SIGRTN circuit open
PCM
ICP sensor
Disconnect the ICP sensor to induce the opposite DTC.
Perform the Key On Engine Off self-test.
Is DTC P2285 present?
Yes No INSTALL a new ICP sensor. GO to Q7 .
Q7 CHECK THE ICP SENSOR SIGNAL FOR A SHORT TO VOLTAGE
Key off.
Disconnect the PCM.
Key on, engine off.
Measure the voltage between the ICP sensor signal circuit pin C, harness side and ground.
Is any voltage indicated?
Yes No REPAIR the circuit. GO to Q8 .
Q8 CHECK THE ICP SIGRTN CIRCUIT FOR AN OPEN
Key off.
Measure the resistance between the ICP sensor SIGRTN circuit pin A, harness side and the PCM engine connector pin 25, harness side.
Is the resistance less than 5 ohms?
Yes No INSTALL a new PCM. REPAIR the circuit.
Q10 CHECK THE VREF CIRCUIT FOR AN OPEN
Key off.
Disconnect the PCM.
Measure the resistance between the ICP sensor VREF circuit pin B, harness side and the PCM engine connector pin 36, harness side.
Is resistance less than 5 ohms?
Yes No GO to Q11 . REPAIR the circuit.
Q11 CHECK THE VREF CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between the ICP sensor VREF circuit pin B, harness side and ground.
Is resistance greater than 10, 000 ohms?
Yes No INSTALL a new PCM. REPAIR the circuit.
Q12 ICP SENSOR BIAS CHECK
Note: Verify engine oil temperature (EOT) is greater than 82°C (180°F).
Key on, engine off.
Access the ICP PID.
Is the ICP PID voltage between 0.18 and 0.24 volts (Early Build) or 0.15 and 0.35 (Late Build)?
Yes No REFER to Section 3 if a driveability concern exists. INSTALL a new ICP sensor.
Q13 ICP SENSOR INTERMITTENT CHECK
Visually inspect the ICP sensor harness and connector for damage, corrosion, or incorrect routing.
Access the ICP PID.
While monitoring the ICP PID, wiggle, shake, and bend small sections of the wiring harness while working from the sensor to the PCM.
Is there any change in the ICP PID value, or is a concern present?
Yes No REPAIR as necessary. The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

 

I had a similar problem where all signs pointed to the ICP sensor.

I had unusually long cranks and mediocre performance. I had cranks so long, I often wondered if the truck was even going to start.

The sensor and pigtail were spotless too.

I replaced the ICP sensor and haven't had a problem since.

 

When you get home, would you mind posting the ICP pressure = ICP voltage?

 

Be glad to.

Found this post with the wire colors. Not sure if all years are the same.

Here is a way of checking to see if you have sufficient high pressure oil without having a gauge or adapter. Strip back the wires about an inch away from the icp sensor connector. Obtain a digital multimeter and set it for voltage (DC). The bn-wh wire is a five volt reference, leave that alone. Strip back the db-lg signal wire and the gy-rd ground wire. Put positive lead on a dark blue-light green wire and negative lead on gray-red wire. Have an assistant crank truck, you need a minimum of 0.82 volts (500 psi) for the truck to start, if you are getting greater than that then you have sufficient high pressure oil.
__________________

 

This is the same issue I have. ICP sensor is clean, no oil present and no leak around the threads of the sensor going into the valve cover. Inspection of the pigtail shows its been replaced and therefore I believe it was a new sensor then to. My best guess is the repair is two years old. The hunting idle is within the last year or so.

I'm going to unplug mine and see what happens.