What does the service engine soon light mean on a Ford F-150?

A: Code P0133 reads "Bank 1 Sensor 1 circuit slow response"; meaning the front oxygen sensor (located before catalytic converter) has slow response time to the changes in the air-fuel mixture. This could happen for many reasons, for example: bad oxygen sensor itself, bad or contaminated airflow sensor, intake manifold leak, exhaust leak, problem with the wiring, etc.

Visit your local dealer or a mechanic for proper testing procedure to pinpoint the exact cause. ---- A: The code P0102 reads "Mass air flow circuit low input". There is a certain procedure to test Mas Air Flow sensor (MAF) for proper operation. When you bring your car to a dealer, they will perform this procedure to check if the sensor is faulty. Mass Air Flow sensor failure is very common. ---- A: The code P1400 reads "DPFE Sensor Voltage Low" (Ford, Mazda). Often it's caused by bad DPFE sensor or clogged EGR passages. Visit your local Ford dealer, they will be able to help you. ---- A: P1000 is not actually a trouble code. It just means that the Readiness code has not been set yet or in other words, the engine computer hasn't completed testing certain emission control components. If there is no other problems with the car emission system, the code P1000 will disappear after driving for some time (the drive circle must include idling, stop and go traffic, acceleration and steady cruising). ---- A: Code P0171 reads "System too lean (Bank 1)" and code P0174 reads "System too lean (Bank 2)" What it means is that the engine is running lean. There are many possible problems that may cause the air-fuel mixture to be lean: Defective or contaminated airflow sensor, intake vacuum leak, dirty fuel filter, etc. There are certain tests to be performed to find the exact cause of the problem. Common problems with Ford engines are defective airflow sensors and vacuum leaks. As of my knowledge, Ford issued Technical Service Bulletin on this problem, you can check it at Alldata DIY.

I'd suggest to visit your local Ford dealer, they will be able to repair the problem properly. ---- A: Yes, overfilling the gas tank can trigger the "check engine" light to come on. Modern cars are equipped with an Evaporative System that prevents gasoline vapors from escaping into the atmosphere. When we overfill the gas tank, the excess gasoline can enter the part of the Evaporative system called Charcoal Canister and this can cause some problems. Don't fill the tank past the first click of the pump. Check your owner's manual.