2022 Ford ranger lariat tremor P139C

[WolfssRain]

Check engine light came on my truck yesterday while driving. I drove it today and the engine light is off. Does the emissions sensor going out? Should I be concerned and take to a mechanic?

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[RangerBill]

Check engine light came on my truck yesterday while driving. I drove it today and the engine light is off. Does the emissions sensor going out? Should I be concerned and take to a mechanic?

Have the DTC codes read with a scanner. That should point you in the right direction.

 

[airline tech]

So you scanned and pulled code P139C?

 

[JerryRange]

P139C is usually related to the glow plug circuit, so if the light's off now it might just be a glitch but I'd still get it scanned to see if the code is still stored.

 

[airline tech]

For the Ranger - it's specifically for the DPFE - and it's the code that should display for all the no code but have Buck Surge.
It will only set - when EGR is active and flowing - as the DPFE is what sets the code.
So, it's one of the following - DPFE Sensor itself or moisture or restriction in the (High Pressure Ref) small EGR Tube port - (These are the most common and most likely)
Or upstream (flow issue) from biased Exhaust Press Sensor or Restricted EGR Cooler that produced (caused) the DPFE to register (under reporting) - which is basically what P139C is.
It did not see the expected (Positive) flow response when the EGR Valve opened.
Now the reason for it (running fine) is that P139C will set the EGR system to disable, so with EGR disabled you have no flow to the DPFE and symptoms will not be present

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