• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Getting P0231

fritz1990

fritz1990

New Member
Messages
15
Reaction score
0
Location
Kansas
I used the search but only gives me the code numbers. I would like to know what this means and what to do about it. It just came on this morning and I have to take my son to College tomorrow. Your help would be greatly appreciated!

I have 5 psi while cruising, and very recent filter chagne. Runs fine with no problems that I can tell.

P0231 Fuel Pump Feedback Circuit Low Voltage

Regards, Jeff
 
I can hear it running and it has 5 psi cruising, I have a fuel presssure gauge on it.

I carry a spare LP maybe I will change it this morning before we leave if no one else chimes in.


By the way I now have 202,000 mi.

Thanks!

Regards, Jeff
 
OK that is weird. If it doesn't have power to the lift pump circuit, there is no way you can get 5 PSI at idle or any other time. I wonder if there is a voltage threshold that triggers the code yet would run a lift pump? Anybody?
 
Got my son to college and back. Didn't get a chance to change LP but I cleared the code before we started home and it was back within 40 miles. Held 4-5 psi the whole trip. Gonna go ahead and change the LP in the next couple days and see what happens.

I assume from your post that the code means the LP is on it's way out or has wiring problems?

Regards, Jeff
 
PO231 IIRC is a IP code, not lift pump code, I'm away from my manuals to say for sure. That said if it is the lift it could be lower than the threshold but still capable of pushing fuel, as indicated by 5 psi on gage. 2 voltage sources OPS & PCM on OBDIIs, common point is the GND which if dirty would cause lowered voltage. It's located on upper frame rail drivers side, just aft of where the filler neck tube runs over to the fuel tank fill, which is cheap & easy to to rule out as a possibility.

Hey Fritz, I see 3:42 in your signature, You sure ??? K1500 usually came with 3:73, 2wd C1500s were the ones with 3:42 in most cases.
 
Thanks for the confirmation Ratt, with that my best bet is poor gnd.

Fritz check voltage by unplugging the lift pump and check across the 2 pins black is the GND, read volts, then white or grey I can't bermember color, to a good solid clean gnd and see if you have a big voltage difference both readings, that will confirm a bad GND.
 
Turbine Doc said:
PO231 IIRC is a IP code, not lift pump code, I'm away from my manuals to say for sure. That said if it is the lift it could be lower than the threshold but still capable of pushing fuel, as indicated by 5 psi on gage. 2 voltage sources OPS & PCM on OBDIIs, common point is the GND which if dirty would cause lowered voltage. It's located on upper frame rail drivers side, just aft of where the filler neck tube runs over to the fuel tank fill, which is cheap & easy to to rule out as a possibility.

Hey Fritz, I see 3:42 in your signature, You sure ??? K1500 usually came with 3:73, 2wd C1500s were the ones with 3:42 in most cases.
Click to expand...

Thanks I will check that out this weekend. Been crazy busy at work.

Yes I have 3.42's in the diff's, as I ordered the truck this way new. The dealer was trying awfully hard for me to stick with the 3.73's but I ordered the 3.42 and glad that I did. I do alot of highway driving only and at 70MPH puts me at about 1950 RPM's. I did do some math before ordering the 3.42. ;)

Thanks again, and I will post back findings this weekend.

Regards, Jeff
 
i got 3.42s too. so not all k1500s got 3.73s. but for 185 hp and tall gears it has pretty good accerlation i think for a sub 6 thousand pound truck
 
Finally got around to checking things out. I am mechanically inclined but electrically challenged.

I unlugged the LP at the LP and voltage across the two wires was 12.80 I then grounded the ground wire on my meter to the frame and it showed 4.5 volts. Doesn't seem right to me but I don't know what this means.

If you think this is bad ground where do I check? Is there a specific place for this one? Checked all batt connections also while I was out, run Optimas so no corrosion issues.

As in my sig all the grounds were cleaned 12,000 miles ago for the first time and only did it because you guys have said they need to be done. I am at 202,000 mi now.

Thanks!

Regards, Jeff
 
You must log in or register to reply here.
Back
Top