Mercury Marauder 4.6L Turbo P0108 and P0405 Diagnostic Guide
My Mercury Marauder with a 4.6L Turbo engine is showing two diagnostic trouble codes: P0108 and P0406. I have confirmed good vacuum pressure, and the vehicle runs smoothly under normal conditions. However, after driving on highways and exiting, the car begins to stumble significantly—requiring me to fully open the throttle for it to regain power. I'm wondering if this could be related to a faulty PCM signal, as the engine actually performs better once the check engine light comes on.
Start with diagnosing P0406. Please share your findings. Refer to BBBind.com for detailed wiring diagrams. Potential causes of a P0406 code include: - EGR sensor signal circuit shorted to B+ (battery voltage) - EGR sensor signal circuit shorted to the 5-volt reference circuit - EGR sensor ground circuit open - EGR sensor signal circuit open - Internal failure in the EGR sensor or solenoid - Debris lodged in the EGR valve, causing it to remain stuck open or closed For more details: https://www.bbbind.com/p0406