Check Engine Code P0402

[Chimchim]

My 2021 Ranger w/ 40,000 miles threw a P0402 check engine code - EGR Flow Excessive.

I did a little googling, but it seems like I wouldn't have this issue (carbon build up) at 40,000 miles?

Anyone else run into this?

It happened once, so I took it to the dealer and they just scanned and deleted it. A couple of days later it came back again, same code, so I erased it and and waiting to see if it pops back up.

Thoughts?

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[Trigganometry]

The part I listed in this post seem to be the culprit for the code being thrown in most cases. It's fairly cheap part and I picked up a spare for myself if it ever happens to my ride. https://www.ranger5g.com/forum/threads/p04f0-code-evap-system-problem.23985/post-544804

 

[Chimchim]

Cool, thanks for the input.

 

[ericm88]

I had the same issue a few weeks ago. Replacing the sensor referenced here fixed the issue.
https://www.ranger5g.com/forum/threads/p0402.25330/

 

[Lateknightucd]

I just had the same issue. 22K on my 2023 Ranger. It's under warranty still but the next dealer appointment is in three weeks. Plus they don't have the valve in stock so it's unlikely they'd turn the job around in a day. I had them order the part and it'll be here Monday. Fingers crossed it's this valve and it also clears up the partial throttle surging issue.

 

[Lateknightucd]

I just had the same issue. 22K on my 2023 Ranger. It's under warranty still but the next dealer appointment is in three weeks. Plus they don't have the valve in stock so it's unlikely they'd turn the job around in a day. I had them order the part and it'll be here Monday. Fingers crossed it's this valve and it also clears up the partial throttle surging issue.

Following up on this. The install was super easy and would have been easier if I didn't accidentally remove the sensor from the bracket, leaving the bracket on the engine rather than taking the whole assembly out. The new sensor went back on fine but the angle with the wrench and socket was much more awkward this way. On test drive the truck felt brand new. No lurching at partial throttle at all. Interestingly, I haven't noticed the cold shifting issue I was having or the crazy "thunk" when slowing down right after speeding up (think all the stop signs in grocery store parking lots). I'm wondering if the EGR issue causing surging was also messing with the shifting and torque converter lockup. Obviously, there's a TSB for a lot of those transmission issues but I have a '23 (so apparently the updated CDF drum) and was having similar symptoms to the early MY guys but all that has gone away after the sensor replacement. Since the part is relatively cheap and quick (certainly compared to the tranny TSB) this might be a worthwhile first step to try. Also, my old sensor had a ton of moisture as reported elsewhere.

 

[gkostolny]

Thanks for this pointer! My truck started throwing this code intermittently a couple months ago, and in retrospect drivability had suffered, but it was gradual so I didn’t realize how much until I replaced the sensor this morning (those hose clips were a pain in the ass to remove). Whole different truck. Glad to have this resolved.

I had the same issue a few weeks ago. Replacing the sensor referenced here fixed the issue.
https://www.ranger5g.com/forum/threads/p0402.25330/

 

[TheDo114]

Same situation, dealer replaced mine and no more code. I did not notice a change in behavior.

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