What do these codes mean?

[f$nsho]

I just ran the codes on my '93 MTX and came up with the codes 542 and 557.
I did a search on previous posts and the 542 is pretty well explained. For the 557 code -Low speed pump relay primary circuit fault- I could not really find anything. Does anyone have any insight what this code means and what I possibly can check out?

Much appreciated,
Rein

 

[Mr Anonymous]

Your fuel pump is probably on its way out.

 

[sdpatt]

If the fuel pump is healthy, it may be the integrated control module with the fuel pump relay above the radiator that is failing.

 

[f$nsho]

Before I go and start replacing the fuel pump or the integrated control module, is there a way to check which one of the two is the culprit here?

I do have a total lack of power especially after the secondarys open up, but I just in the middle of my 60k service that I hope will take care of all of this. I should know pretty much by tonight.

 

[oldkat]

I have the same problem on my 92 mtx. There is no power when the secondaries open at 4000 rpm; pops and bucks. Diagnostic check shows codes 557 and 524. The car starts easily and drives pleasantly untill the foot goes to the floor. The fuel pump is brand new as are all filters. The engine revs easily as long as there is no load on it.