I have a 1992 F150 with a 5.0L engine. My check engine light is on. I borrowed a code reader and I have a code 22. I was told it is the map sensor. I replaced it but the light is still on after I cleared it. As soon as I turn the key on without running the engine I get a code 22. Where do I go from here?

 

Make sure it has power and vacuum.

 

It has vacuum and 5v to one wire.

 

You may have a broken wire. Check the continuity of all three wires. All three wires go to the computer. One wire, the light green with a black stripe, goes straight to the computer. The brown one with a white stripe is spliced to the TPS and EVP and goes to the computer. The grey one with a red stripe is spliced to many other sensors then goes to the computer. One of the splices may be coming apart. I had a splice come apart on my truck.

 

Thanks, is the other wire a ground? I will check it tomorrow when I get home from work. There was also a code 23 for the tps sensor. I replaced it and it is gone. I had a bypass coolant hose spraying coolant all over the tps sensor.

 

One power, one ground and one signal. It gets power and ground from the computer and sends the signal there.

 

I checked it out, with the truck running or just key on I have 5v at the brown with white stripe, 2.55v at the light green with black stripe and ov at the gray with red stripe. Is the gray with red stripe the ground? I put a test light with its ground wire on the battery positive post and touched the gray with red stripe and it lite up. That means it is a ground. Do I need to trace the gray with red stripe and see if it has continuity to the computer? Without a wiring diagram how do I know where it is on the computer or other sensors? Thanks for your time helping me.

 

You don't need to test the other sensors since you didn't get a code for them, but I wanted to let you know that those wires ran to them because that means there is a splice in the wire somewhere and splices have been known to come apart. The wiring diagrams don't show which is ground or power which is why I didn't say, but now that you have tested them you know. Brown with white stripe is power and gray with red stripe is ground. The light green with black stripe is the signal and should vary with different amounts of vacuum. You should check all wires for continuity from the sensor plug to the computer. The wires will be the same color on the computer plug.

 

All three wires have good continuty. I have a ground back to the ecm at gray & red. The light green & black has 2.5v at ecm and the power ground at pin 40 has a ground. I was told the ecm probably is bad. It will take a few days to get one. Thanks

 

No problem, let us know how it goes. I like to make damn sure everything checks out before changing the ECM.