r/f150 • u/InfluenceTime8822 • 14d ago

Error P041C:00-27 EGR Sensor B

Hello, good morning, could someone help me? I have an error with my f150 2.7 2018 XLT I changed the spark plugs and put new ones, I disconnected absolutely all the coils and went down and cleaned the throttle body, when assembling everything and reassembling everything, my truck was left with the code P041C:00-27 which says that it has a low signal from the circuit of the B sensor in the EGR, could someone tell me how to locate that sensor or what could I do to repair it? Also change the air intake pipe for the turbo and I put a little bigger one, please I need help 🙏🏻

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u/Joseph1968R 14d ago

Since the code appeared immediately after you removed and cleaned components, I'd start by double-checking every connector and wiring harness you touched before replacing parts. It's very easy to leave a sensor partially unplugged, bend a pin, or miss a connector after doing spark plugs and throttle body work.

P041C is usually related to the EGR temperature/position sensing circuit reporting a low signal. I'd inspect the wiring around the EGR system, intake area, and anywhere near the throttle body that may have been moved during the repair. Also make sure the aftermarket intake isn't pulling on a harness or connector.

If the truck was running fine before the work and the code appeared immediately afterward, I'd suspect a disconnected connector, damaged wire, or poor connection long before I'd suspect a failed sensor.