Code P0231 what does it mean?

87lc2

Member
Oct 16, 2005
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Finally got my tuner and its showing this code:

P0231 - fuel pump secondary circuit

Car runs fine and really dont know what this means, anyone run into this before?

I did take out the fuel pump fuse last week while the car was running to change the fuel filter, could this code have been set then? Any info appreciated.
 
Im thinking it wont come back either but if you pull the fuse while its running and let the pump shut down that way there is hardly any fuel in the lines when you go to take the filter off. Works pretty well, except for the code...
 
Im thinking it wont come back either but if you pull the fuse while its running and let the pump shut down that way there is hardly any fuel in the lines when you go to take the filter off. Works pretty well, except for the code...



You do realize that is one of the single most destructful things you can do to your fuel system right? You basically ran your engine out of gas which has multiple risk of side effects.

Next time just remove the filter and clean up the minimal amount of fuel that comes out with it. I would highly reconmend against you ever doing this again.
 
I just cleared it with the SCT so hopefully it wont come back. How is that destructive to the fuel system? Its essentially the same as pulling the inertia switch in the trunk, which is what everyone else does when they change the filter. Then you simply bleed pressure at the line and you dont get fuel in your eyes when the filter comes down.
 
Obviously, it's not that destructive. The biggest risk would be spark jump to the fues as you pull it out.

Yes, the engine runs lean, but seriously, at idle it isn't going to hurt anything. The cylinder pressures are so small and the load on the engine insignificant.

It may not be an approved method by ford service, but I don't see it causing any damage.
 
I'm not so worried about running lean as the injectors have issue's because they were trying to squirt while they were dry.

I'm sure the chances of damage are small but why risk it? The amount of fuel that comes out of the lines when you change a filter can easily be taken care of with a paper towl when pulling the lines off. Not sure I agree with the risk when there really isn't that big of a need for it. Even pressing the inertia swich imho is a bad idea.