2010 Ford Explorer P0443 and P0403

Share your FORScan experience with other users

2010 Ford Explorer P0443 and P0403

Postby gdcockra » Fri May 19, 2017 9:11 pm


Hi Everyone,

My 2010 Ford Explorer XLT 4.0 V6 started giving me a P0443 and P0403 codes.
I hooked up and took a look and I can see the EGR CMD change and EGR ERR swing between +100 and -100%.
The Evap Valve I tested by hand and it cycles fine and using Forscan I can see the pressure change when the CMD to the EVAP goes up, pressure goes down. I can hear it click when it cycles on.
I tested voltages at the ECM connector and they are all within spec, I even changed the EGR valve just in case.
I checked for a short to ground on all wires, checked Vacuum at the EGR for leaks, none there. Inspected cabling and nothing was rubbing on anything, all still in the jacket and holders.
So figuring it was a bad ECM I sent it off. Today they call me and say no issue with the ECM either. Is it possible the connector for the ECM is not making a good contact? I have no real way of testing it.
The tech suggested maybe a software glitch as he sees quite a few of them come in for the same codes and he finds no issues with the ECM. No one ever calls him back to let him know what they did to fix it.
ForScan cannot actuate the EGR valve independently so it is difficult to test. It would be a nice feature to have FYI.
Engine runs completely smooth, no drivability problems what so ever. Just not going to pass inspection and Fuel Consumption is down to 11mpg

So does anyone have any more ideas on finding the cause other than a software update as I don't have the software to update it with.

PCM - Powertrain Control Module
Part number: 9L2AED
Strategy : PWGF0A8
Copyright Ford Motor Co. 2008

===PCM DTC P0403-FF===
Code: P0403 - EGR valve position control circuit
Module: Powertrain Control Module
Diagnostic Trouble Code details
EGR valve position control circuit
Open Circuit
Short circuit to ground or battery
This DTC may be caused by :
Damaged or worn vacuum hose
EGR valve assembly
===END PCM DTC P0403-FF===

===PCM DTC P0443-FF===
Code: P0443 - Purge valve circuit fault
Module: Powertrain Control Module
===END PCM DTC P0443-FF===

The ECM came back yesterday, it was very clean. I hooked it back up and pulled up forscan, using the Oscilloscope for the EGR and EVAP sensors it was a night and day difference. All sensors were working correctly.
I called SIA Electronics who I had sent the ECM to and spoke to the tech. He said they sand blasted it so it would be clean before they disassemble it to ensure no dirt or grease get into the circuits. They also sand blasted the pins on the ECM.
So I took the connectors off the ECM and used an Electronics Parts cleaner to flush them out, took the EGR connector and cleaned it and finally the EVAP valve connector and cleaned it out. Took it out for a test drive while watching the Oscilloscope on my laptop and all looked great.
Drive Cycle Monitor cleared including the EGR which would not clear before.

So now I needed to know why, I have had this vehicle a month, I called the dealer and asked what they used to make the engine bay so clean and shiny. They degreased it then used a Silicon based dressing to make it shine.
So I ran some tests on some engine metal and sure enough, DC Resistance, ran a capacitive test and it was present.
So this now makes sense, this got onto the ECM pins, before I could see spikes on the ECM ERR PID, Now I see smooth voltage changes. Spikes indicate a capacitive effect. If you put a probe into the ECM connector to look at the voltages you will see them but the ECM could not. ECM pins.
So this was the Engine Dressing used by the dealer to make it shine, Silicon by itself is not a good conductor even though it is used to make transistors, it takes added elements to get it to conduct. Now to clean out EVERY connector in the engine bay.

Posts: 2
Joined: Wed May 10, 2017 5:05 pm
Vehicle: Explorer, Gas, 4.0L, 2010, F-150, Gas, 5.4L 2007

Re: 2010 Ford Explorer P0443 and P0403

Postby gdcockra » Wed May 24, 2017 2:58 pm

See update in original post.
Posts: 2
Joined: Wed May 10, 2017 5:05 pm
Vehicle: Explorer, Gas, 4.0L, 2010, F-150, Gas, 5.4L 2007

Re: 2010 Ford Explorer P0443 and P0403

Postby drewmcg » Sat Jul 15, 2017 2:01 pm

wow. good info.
Posts: 1
Joined: Fri Jul 14, 2017 9:48 pm
Vehicle: Ford Explorer 4.0L SOHC XLS 2002

Re: 2010 Ford Explorer P0443 and P0403

Postby Wangstang » Tue Jul 18, 2017 3:14 am

Thanks for the update
Posts: 14
Joined: Sat Jul 01, 2017 1:50 pm
Vehicle: 05 Ford Escape, 3.0L V6 AutoAWD

Return to Diagnostics and Maintenance using FORScan

Who is online

Users browsing this forum: kazu3311 and 8 guests