P0402 Code - Exhaust Gas Recirculation Flow Excessive Detected

[Jacobpaulk]

Hello! This is my fist post in the Bronco6G forum - thanks for the add!


I recently purchased a 2021 Outer Banks (2.3L) on April 1st. On the way home from leaving the dealership it threw a CEL. Code P0402 - Exhaust Gas Recirculation Flow Excessive Detected. I searched the forum but didn’t see anyone else that has posted about this issue.

Truck is at 40,000 miles - cleared the code and drove it approx 200 miles before the code returned.

There are no obvious signs of excessive EGR flow - no bucking, surging, stalling, or rough idle. Fuel economy is not great which could be a sign of EGR issues - around 15 MPG - but I’m mainly attributing that to the 37” tires. I do not see any loose connectors or vacuum lines around the EGR or intake. I did fill up with premium fuel - the CEL came on around 20 miles after fill up.

Looking for advice on what you all believe the issue could be or if anyone else has experienced this issue? Just wanting to research some more before I start tackling the issue.

I have purchased a replacement EGR valve, EGR gasket, and Differential Pressure Sensor but have not installed yet.

Side notes in case anyone asks: The dealership that I purchased from (not Ford) is about 1.5 hours away from me and do not seem motivated to fix the issue even though it happened same day - that’s okay with me, I just want to fix the problem. This issue won’t be covered by Ford since the truck is out of the 3yr/36k warranty. It also won’t be covered by the extended warranty I purchased since it is an emission component. Also - when we checked the code with a scanner, the truck had been driven around 10,000 miles and warmed up approximately 251 times since the last CEL was cleared (or battery disconnected) so I do not believe the dealership was aware of this issue - it was likely coincidence. They only had the truck for a day before I purchased it.

Attaching a photo of my Bronco here and the code reader data - thanks again for the add and looking forward to learning more about these trucks in this group!

Sponsored

 

[Brian_B]

Did it pop back up once you cleared it? Or did you fire the parts cannon before taking aim?

Given that everything else sounds normal, fuel economy sounds normal for your setup, and nothing looked crazy under the hood... I'd wait for the code to come back before doing anything else. Decent chance it may never come back.

 

[Jacobpaulk]

Did it pop back up once you cleared it? Or did you fire the parts cannon before taking aim?

It came back after around 200 miles of driving unfortunately.

 

[Brian_B]

It came back after around 200 miles of driving unfortunately.

Ah bummer.

Just that code and nothing else to go with it? 50/50 shot on it being the valve or the sensor I'd say without any other info. Start with whichever is cheaper or easier to get at?

 

[Ducati1098]

Probably needs the DPFE sensor. They aren’t uncommon.
But that’s just a guess. Nobody on here is going to be able to diagnose it for you.

 

[Jacobpaulk]

Ah bummer.

Just that code and nothing else to go with it? 50/50 shot on it being the valve or the sensor I'd say without any other info.

Yeah, just the P0402 code. No noticeable issues when driving - everything seems fine.

 

[Jacobpaulk]

Probably needs the DPFE sensor. They aren’t uncommon.
But that’s just a guess. Nobody on here is going to be able to diagnose it for you.

Thanks man. I understand that

 

[Ducati1098]

Thanks man. I understand that

Can you read live DPFE pressure and voltage with that scan tool you took pictures of?

 

[Jacobpaulk]

Can you read live DPFE pressure and voltage with that scan tool you took pictures of?

That’s a great question - I’ll have to check on Thursday. It’s a friend’s scan tool - I have a much more basic version.

 

[Ducati1098]

That’s a great question - I’ll have to check on Thursday. It’s a friend’s scan tool - I have a much more basic version.

Sounds good. If you can monitor it and you have a hand vacuum pump, I can post the pinpoint test on how to check the DPFE sensor operation

 

[PowerBronco]

Would this type of thing be covered under the 8yr/80k emissions warranty that is provided? Not saying don't fix it yourself, just curiosity on my part.

 

[Ducati1098]

Would this type of thing be covered under the 8yr/80k emissions warranty that is provided? Not saying don't fix it yourself, just curiosity on my part.

No. Depending on what it needs, the EGR valve would be covered under powertrain (5/60) and the DPFE sensor is only covered under bumper to bumper (3/36)

 

[Brian_B]

Would this type of thing be covered under the 8yr/80k emissions warranty that is provided? Not saying don't fix it yourself, just curiosity on my part.

Ford warranty coverage:
"No."

 

[Jacobpaulk]

No. Depending on what it needs, the EGR valve would be covered under powertrain (5/60) and the DPFE sensor is only covered under bumper to bumper (3/36)

Interesting - my local Ford said EGR is not covered under powertrain warranty. I can’t seem to get a straight answer from the place I bought it or Ford which is why I’m looking into fixing it myself. Ford quoted me $200 just for diagnostic.

 

[Ducati1098]

Interesting - my local Ford said EGR is not covered under powertrain warranty. I can’t seem to get a straight answer from the place I bought it or Ford which is why I’m looking into fixing it myself. Ford quoted me $200 just for diagnostic.

I'm not sure why they would even say that without knowing what the causal part was lol
But yeah if they do diagnose it, and it ends up not being covered, then you would obviously have to pay their quoted diagnostic time.

Sponsored