I am pulling a 542 code-
(O,M) Fuel pump open, bad ground or always on-- Power/Fuel pump circuits


Has anyone dealt with this issue and what was needed to fix it? I just had a fuel pump put in last weekend. Maybe the electrical connector at the tank?
Any advice is appreciated.

 

What is the truck doing? My truck had(s) a condition where it will run the tanks non stop and wont shut the pumps off. I think I may have fixed it but if not I am going after the computer. I had a bad connection in the PCM relay

 

It starts and runs but it won't run smooth, it sputters, the check engine light flashed briefly, and loses power at highway speed. I cleared the codes, then pulled the code with the truck warmed up,engine off and the key on. This is the only code that was thrown. I have heard it may be the fuel pump relay? I guess I will start with that and see where it goes.

 

Do you lose power at 45 mph by any chance? If the vacuum lines for the vacuum reservoir get switched around, it will throw a code, cause a cel and lose power at 45mph. Similar issues with the charcoal canister lines being switched around backwards. If you've just done a fuel pump, I felt it important to see if you replaced.any vacuum lines that you could have reversed.

 

I will take a look at them and see if something got switched around or came loose. Sounds like an inexpensive place to start. Thanks