Fuel pump code issues

The_Wolf222

Member
Mar 8, 2020
6
1
13
18
New Hampshire
Okay so here are the codes I’m pulling

542- fuel pump secondary circuit failure
543 - fuel pump secondary circuit failure (the book says the same thing for both codes, no idea why)
556 - fuel pump relay primary circuit failure

The car runs, but at about 3/4 throttle it gets stuck at ~4500 rpm and doesn’t accelerate, just makes a strange noise. The car acts better with a full fuel tank, and today when it was acting up I managed to pull the above codes.

I tested the ccrm votages (I believe I did it correctly but I’m not 100% certain) and I got the correct voltages for the inertia switch and the relay.

Can anyone help me figure out what’s going on? Is it possible my fuel pump is weak and needs replacing? If you have any further questions please ask. Thank you!
 
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DualXhst289

Member
Aug 28, 2009
23
1
13
Okay so here are the codes I’m pulling

542- fuel pump secondary circuit failure
543 - fuel pump secondary circuit failure (the book says the same thing for both codes, no idea why)
556 - fuel pump relay primary circuit failure

The car runs, but at about 3/4 throttle it gets stuck at ~4500 rpm and doesn’t accelerate, just makes a strange noise. The car acts better with a full fuel tank, and today when it was acting up I managed to pull the above codes.

I tested the ccrm votages (I believe I did it correctly but I’m not 100% certain) and I got the correct voltages for the inertia switch and the relay.

Can anyone help me figure out what’s going on? Is it possible my fuel pump is weak and needs replacing? If you have any further questions please ask. Thank you!

I just had those codes, as well as others, on my 95 Cobra. I changed the fuel filter and added fresh gas (car has not been on road for over 2 years) and those fuel codes have not been back since. Worth a shot.
 

The_Wolf222

Member
Mar 8, 2020
6
1
13
18
New Hampshire
I just had those codes, as well as others, on my 95 Cobra. I changed the fuel filter and added fresh gas (car has not been on road for over 2 years) and those fuel codes have not been back since. Worth a shot.
I changed the fuel filter shortly after I posted this and it didn’t help. Turns out it was the fuel pump all along! I’ve been dealing with a car that barely runs for like 4 months because of the damn fuel pump haha
 
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DualXhst289

Member
Aug 28, 2009
23
1
13
What’s the issue? I might be able to give some sort of guidance with all the stuff this car has put me through haha.

In a nut shell, car runs for 20 mins, stalls, will then start back up immediately.