Well I finally bit the bullet and paid Ford to check out my 1995 F350 dually. I could't find a code reader that would read my truck. The code is a P1212. The tech said that the ICP had shorted out because of a wiring issue and damaged that circuit in the PCM. He said that I would need a new PCM and maybe a new ICP sensor.

Any idea how to determine if this is the case or not. He said that the truck was only reading 725 psi of oil pressure to the injectors and that no matter what RPM it didn't change, so he ran a new wire from the ICP sensor to the PCM and he said it was the same. He wanted to make sure it wasn't the wiring harness.

My question is, before I go spending big bucks on a new PCM. Is there any other thing that would be affected if the PCM was bad? Or, should I start by replacing the ICP sensor first?

Either way, where would be the best place to buy the parts?

B.T.W. This problem was all my fault by trying the ICP mod and shorting out the wires myself........trying to switch resistors back and forth and not securing them well.......Thought that might help a bit....

Thanks in advance for any and all help.

 

I found some awesome information after I posted this thread. I guesss I will be doing some checking in the morning.


<TABLE style="FONT-SIZE: 10pt" cellSpacing=0 cellPadding=1 width="95%"><TBODY><TR><TD><CENTER></CENTER>
SIGNAL FUNCTIONS
The Injection Control Pressure (ICP) sensor is a variable capacitance sensor that when supplied with a 5 volt reference signal from the PCM produces a linear analog voltage signal that indicates pressure.
The ICP sensor's primary function is to provide a feedback signal to indicate injection control pressure to enable the PCM to command the correct injector timing and pulse width and the correct injection control pressure for proper fuel delivery at all speed and load conditions.
FAULT DETECTION MANAGEMENT
If the PCM detects a malfunctioning ICP sensor, the CHECK ENGINE lamp will illuminate. The PCM will go to open loop control of injection control pressure. (Operate from an estimated ICP pressure.)
At idle, the NGS tool will display a fixed PID value of 725 PSI for ICPA when a signal fault is present.
<CENTER></CENTER>
<CENTER>After removing connector always check for damaged pins, corrosion, loose terminals, etc.</CENTER>
<TABLE style="FONT-SIZE: 10pt" border=1 cellSpacing=0 cellPadding=3><TBODY><TR><TH colSpan=3>Connector Checks to Ground (B-)</TH></TR><TR><TH colSpan=3>(Check with Sensor Connector Disconnected and Ignition key off, all accessories off)</TH></TR><TR><TD align=middle>Test Points</TD><TD align=middle>Spec.</TD><TD align=middle>Comments</TD></TR><TR><TD align=middle>A to Grd.</TD><TD align=middle>< 5 ohms</TD><TD>Resistance to chassis ground check with key off, if > than 5 ohms harness is open.</TD></TR><TR><TD align=middle>B to Grd.</TD><TD align=middle>> 1000 ohms</TD><TD>Resistance less than 1000 ohms indicates a short to ground.</TD></TR><TR><TD align=middle>C to Grd.</TD><TD align=middle>> 1000 ohms</TD><TD>Resistance less than 1000 ohms indicates a short to ground.</TD></TR></TBODY></TABLE>
<TABLE style="FONT-SIZE: 10pt" border=1 cellSpacing=0 cellPadding=3><TBODY><TR><TH colSpan=3>Connector Voltage Checks</TH></TR><TR><TH colSpan=3>(Check with Sensor Connector Disconnected and Ignition Key On)</TH></TR><TR><TD align=middle>Test Points</TD><TD align=middle>Spec.</TD><TD align=middle>Comments</TD></TR><TR><TD align=middle>A to Grd.</TD><TD align=middle>0 - .25 volts</TD><TD>If greater than .25 volts, signal wire is shorted to VRef or battery.</TD></TR><TR><TD align=middle>B to Grd.</TD><TD align=middle>5 volts ± .5</TD><TD>V Ref. check with key ON, if voltage is not in spec., see V Ref circuit</TD></TR><TR><TD align=middle>C to Grd.</TD><TD align=middle>0 - .25 volts</TD><TD>If greater than .25 volts, signal wire is shorted to V Ref or battery.</TD></TR></TBODY></TABLE>
<TABLE style="FONT-SIZE: 10pt" border=1 cellSpacing=0 cellPadding=3><TBODY><TR><TH colSpan=3>Harness Resistance Checks</TH></TR><TR><TH colSpan=3>(Check with breakout box installed on engine harness only)</TH></TR><TR><TD align=middle>Test Points</TD><TD align=middle>Spec.</TD><TD align=middle>Comments</TD></TR><TR><TD align=middle>#91 to A</TD><TD align=middle>< 5 ohms</TD><TD>Resistance from harness connector to 104 pin connector - Signal ground</TD></TR><TR><TD align=middle>#90 to B</TD><TD align=middle>< 5 ohms</TD><TD>Resistance from harness connector to 104 pin connector - V Ref</TD></TR><TR><TD align=middle>#87 to C</TD><TD align=middle>< 5 ohms</TD><TD>Resistance from harness connector to 104 pin connector - ICP signal</TD></TR></TBODY></TABLE><TABLE style="FONT-SIZE: 10pt" border=1 cellSpacing=0 cellPadding=3><TBODY><TR><TD colSpan=3 align=middle>Test Points</TD><TH>Operational Voltage Checks</TH></TR><TR><TD colSpan=3 align=middle>(+) #87 to (-) #91</TD><TH>(Check with breakout box installed in line with the PCM)</TH></TR><TR><TD align=middle>Voltage</TD><TD align=middle>PSI</TD><TD align=middle>MPA</TD><TD align=middle>Comments</TD></TR><TR><TD>1.0 v</TD><TD align=middle>580</TD><TD align=middle>4</TD><TD>Minimum required at engine cranking speed 100 RPM</TD></TR><TR><TD>.88-1.19 v</TD><TD align=middle>540-790</TD><TD align=middle>3.7-5.5</TD><TD>Normal warm idle voltage signal</TD></TR><TR><TD>1.38-1.53 v</TD><TD align=middle>960-1088</TD><TD align=middle>6.6-7.5</TD><TD>Normal high idle voltage signal</TD></TR><TR><TD>3.22 v</TD><TD align=middle>2520</TD><TD align=middle>17.4</TD><TD>Snap accel or full load pressure signal</TD></TR></TBODY></TABLE><TABLE style="FONT-SIZE: 10pt" cellSpacing=0 cellPadding=3><TBODY><TR><TH colSpan=2>Circuit Faults:</TH><TH>Diagnostic Trouble Code Description</TH></TR><TR><TD align=right>1280</TD><TD align=middle>=</TD><TD>Signal voltage was less than .039 volts for more than .2 seconds.</TD></TR><TR><TD align=right>1281</TD><TD align=middle>=</TD><TD>Signal voltage was greater than 4.90 volts for more than .2 seconds.</TD></TR><TR><TD align=right>1212</TD><TD align=middle>=</TD><TD>Signal above 1.625 volts with engine off. (1160 psi, 8 MPa)</TD></TR></TBODY></TABLE>
</TD></TR></TBODY></TABLE>

 

Well a new ICP sensor is cheaper and easier than a PCM. I would start there.
Or if you have a volt ohm meter you can test everything with info posted above.

 

Where would be a good place to purchase a ICP sensor? I have checked on the local parts houses websites and can't seem to find one listed. Thanks.

 

Have you checked with parts guy ed?

 

Your truck has the obd2 port.
Kill 2 birds with one stone.
I would go with a pcm upgrade just so you will not
have trouble pulling codes anymore.
Then move onto the repairs needed if any.

ICP at 725 tells me the pcm is in limp.
(reason unknown as of now)

Bill

 

I'm not sure who that is. Is it someone on here or is there a website?

Thanks.

 

What kind of upgrade is available for this truck on the PCM? Thanks in advance.

 

From the manual....

DO you have another thread on this ?...

Could you link it?...

 

This was the original thread with the problem.

https://www.ford-trucks.com/forums/9...d-no-idea.html

 

Thanks , we'll try not to muck this one up...

Tell us more about the ICP wiring & the Mod..

 

Here:
www.partsguyed.com

 

F4TZ9F838A 95 7.3L ICP sensor list $179.58 check my site for sell price.

 

Back then your trucks weight allowed for it not to be obd2 compliant.
Your truck is obd2 just not compliant. Ford locked the access to the pcm
so only they can get the info needed. They used the non compliant
loop hole so you have to go to the dealer for repair.

A reflash of your pcm can fix the above issue.
Problem now is the pcm could be bad, so it would be a waste to try and reflash it.

Bill

 

ah, ok. That explains why I couldn't read the code with a standard reader. It rained all day today, so I will go by the guide above and check voltages and resistance and see if I can narrow down whether it's the pcm or the icp sensor. Thanks for all your help on this issue.

I also ask him about the excessive fuel consumption and he suggested changing the injector O-rings. The truck does smoke a blue like smoke when I start it up and for awhile aftwards, which I have read that some smoke at start up is normal. I can't really see any smoke after the truck warms up unless I'm really in the throttle.

He said that there were updated O-rings from what was factory on this truck. If so, where is the best place to get the O-ring kit and what kind of money am I looking at to get the kit?

Again, I really appreciate all the help that everyone has given me since I've been on here. Thanks.