Mystery codes 0403 and 0443 - 2010 Ford Explorer XLT 4.0L

[NJayL]

Hello everyone. I was hoping someone could chime in and impart some advice about what else to check on my Explorer. I've had a P0403 and P0443 for the last 4 months.

1. When both codes first threw, I checked the evap purge valve, found it was bad, and replaced it.
2. Codes remained, so I replaced the EGR valve. I was getting ready for a cross-country move and didn't have time to do an in-depth diagnosis.
3. Had to execute military orders across the country and drove from VA to CA. No issues whatsoever. Truck ran great and gas mileage was in the twenties, but codes remained.
4. Replaced the PCV valve.
5. Checked the ground and power to purge valve and EGR, no issues.
6. Checked wiring to purge valve and EGR and did not find any broken wires or chaffing.
7. Removed the PCM and sent to SIA Electronics. They tested it and found nothing wrong.
8. Cleaned PCM wire-harness connectors with water and Dawn soap and let dry for a few days.
9. Codes returned within a day.

I'm stumped. I don't know what else it could be. Maybe the PCM is still bad and SIA misdiagnosed? I really, really don't want to bring the car in to a shop or dealership.
Any advice would be greatly appreciated!

 

[NJayL]

I thought I would update my original thread.

I took the vehicle in to a trust shop near me and this is what they tested:

• Checked circuits between EGR module, fuse 42 and PCM connecter pins 21, 57, 62, and 63.
• Checked circuits between EGR purge solenoid, fuse 42 and PCM connector pin 6.
• "Wiggle tested" engine harness while testing each circuit.
• All circuits have specified continuity, power, ground, and VREF.
• Confirmed test of function for component EGR and evap purge valve.
• Checked vacuum for leaks of EGR system, no leaks found.
• Cleared all codes and reset KAM (Keep Alive Memory).

The codes returned one day after getting it back from the shop. Next steps are to contact Ford and see if they have a software update for the PCM, and if not or it doesn't work, time to shop for an aftermarket or remanufactured PCM. FYSA Ford has a "unknown in length" backorder on PCMs for this vehicle.

 

[Bazz270]

Take your harness apart and start to check for visual damage.

Wiggle test...funny...there is 1000 reason for damaged harness to pass pin point test.

Without any evidence of inner PCM damage or corrosion you have nothing to do with reman PCM swap.

The only way for PCM can be related to EVAP bad connection codes its a visual damage,board corrosion or bent PCM side pins.

In my opinion...

Reman electronics usually it is a piece of junk.even ford or motorcraft.they are possibly use some shady subcontractors with Ford equipment and checklists

 

[NJayL]

Take your harness apart and start to check for visual damage.

Wiggle test...funny...there is 1000 reason for damaged harness to pass pin point test.

Without any evidence of inner PCM damage or corrosion you have nothing to do with reman PCM swap.

The only way for PCM can be related to EVAP bad connection codes its a visual damage,board corrosion or bent PCM side pins.

In my opinion...

Reman electronics usually it is a piece of junk.even ford or motorcraft.they are possibly use some shady subcontractors with Ford equipment and checklists

Bazz270, can I take my truck to you for diagnosing lol? I trying to understand how taking apart the wiring harness would help, since all the continuity for all the pertinent connections has already been confirmed...

The PCM looks great, almost like new. Ford has a 2-year backorder on new PCMs, and even the local dealership parts counter said they are now using OReillys or Automotive Technologies in Houston.

Thanks for taking the time to respond to my post!

 

[Bazz270]

Engine vibration could cause intermediate harness shortcuts.several vehicle modules and wiring circuits starts to operate after one or more warm cycles.

I mean that steady state static resistance check means almost nothing for complicated electric malfunctions during engine vibrations.

 

[NJayL]

Engine vibration could cause intermediate harness shortcuts.several vehicle modules and wiring circuits starts to operate after one or more warm cycles.

I mean that steady state static resistance check means almost nothing for complicated electric malfunctions during engine vibrations.

Ah, got it. That makes a lot of sense! Thank you for the suggestion!

 

[TomacRitchey]

Hi, I know this is an old thread but were you able to solve this problem? I have the same codes right now. Thanks and keep safe everyone!

 

[DSHEP63D]

Hell

Hi, I know this is an old thread but were you able to solve this problem? I have the same codes right now. Thanks and keep safe everyone!

It may be an older thread but with the car market the way it is my ole Exploder has got to last me just a few more years… Having the same issue right now. Found this on another thread
(Found a strange cause for the P0403, P0443 codes | Ford Explorer - Ford Ranger Forums - Serious Explorations

https://www.explorerforum.com/forum...for-the-p0403-p0443-codes.464373/post-3635946

Will be doing this to see if it resolves some issues. It makes sense and I have seen this done on some other German cars. With this having that wonderful SOHC boat anchor in it I can see this being a plausible scenario. Only time and beer will tell…

 

[Sambosat]

Hell

It may be an older thread but with the car market the way it is my ole Exploder has got to last me just a few more years… Having the same issue right now. Found this on another thread
(Found a strange cause for the P0403, P0443 codes | Ford Explorer - Ford Ranger Forums - Serious Explorations

https://www.explorerforum.com/forum...for-the-p0403-p0443-codes.464373/post-3635946

Will be doing this to see if it resolves some issues. It makes sense and I have seen this done on some other German cars. With this having that wonderful SOHC boat anchor in it I can see this being a plausible scenario. Only time and beer will tell…

Link is not working

 

[GB1977]

Any update on this thread? Did it work for you? i now have the same two codes.