When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
2003 F150 XL 4.6 L V8. I’m not a big electrical guy. I do my own oil changes, brake jobs, part swaps, etc. but when it comes to electrical, I’m left scratching my head usually. That said, it rained pretty hard in my area and we had some minor flooding. I hit a puddle that was bigger than I thought it would be and boom, check engine light comes on almost immediately. I pull the codes and they come back for lean banks, P0171 & P0174. So, obviously with the water I think I wrecked my MAF or got it dirty. I didn’t think I got that much water up into the engine bay but I must have. Truck runs fine by the way.
So I swap the MAF, same thing. I get live data from my OBD II sensor and my MAF shows it’s pulling 0.01lbs. Which from what I’ve read is like a factor of 10 off at best. When I hit the throttle, it will get as high as 0.04lbs. So then I check the pigtail that plugs into the sensor, nope, it’s fine. New one doesn’t make it any better. So finally I grab my volt meter and check the wires while the key is on but the truck isn’t running.
This truck has the pigtail that has spots for 6 wires but only 4 of the ports are occupied. The following is a list of the wires and what I think their colors are. Left to right; black & pink, gray & red, black & white, solid red (see the below photo). I read that the black and white is the ground and the solid red is the power. Both read 12 volts when tested so I’m thinking there is a ground short or fault (sorry if that’s the wrong terminology, again I am not an electrical guy).
So, does anyone know where I can find a wire diagram for the truck so I can try to repair this? I can’t afford a whole new harness. I don’t really know what my options are here but I really want/need to be able to do this myself as I can’t really afford to take it to a shop. Please, any help you can give will be very appreciated.
Free resource for service manual and wiring diagrams
If you tested the voltage with the MAF unplugged, the GND definitely should not have 12v. It's possible that wire is shorted to 12v but that should cause the 12v circuit to blow a fuse. If you have a test light, see if the GND pin will light it.
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
