I'm getting an intermittent P0231 code - low voltage condition on the fuel pump secondary circuit. I understand that this is a feedback circuit from the pump, but haven't got any idea on where to go looking for the problem.

'98 burb; 210k miles; FSU relocated (a second time) a few weeks ago to under the front bumper; new fuel pump about 9 months ago.

Any suggestions? Thanks!

Charley

Means you'll be looking into the lift pump circuit - start with the lift pump, unplug\replug each connector, working toward the engine bay, the Oil Pump Switch and the LP relay in the fuse center - should have same voltage on the lift pump as across the battery terminals at idle - could be the OPS, but check thru the circuits first

The fuel pump relay (under the electrical center cover under the hood) could be loose or missing. Don't ask how I know!

Here's an update for the community (I hate folks who ask a question, then disappear).

The problem's fixed. I can't say what exactly the problem was - I just threw money at it, and it went away. I had my local guy replace the relay and the OPS (had one sitting in the shelf for the last few months; figured this was a good time to pop it in). I also had him open the connectors and clean the contacts at the FSD and LP. No more 0231's for several days now.

Sorry I couldn't take the time to really spot the problem, but you folks that do 50+k miles a year know how much free time you have. Always something, e.g., went to breakfast with the boys this last Saturday and got a message from the wife: "Honey?! I just put some old Chinese food down the garbage disposal, and now there's rice bubbling up in the front yard!" Rather than pay a plumber to do it on a Sunday, I laid in some new sewer pipe. With the money I saved, I could afford a mechanic ;)

Good roads to all, and thanks to those who helped.

Regards,
Charley

I see in your signature, intake mounted driver.

That hasn't been found to be best location for it, I as well as several others have had multiple fails that location, invest in a long harness and remote mount driver out of engine bay when you relocate it make sure the transistor nuts on back of driver are still torqued snugly, also make sure ground to IP is still making good connection

My bad. Didn't take the time to update my signature. Indeed, the FSD failed on the air intake. After spending a couple of hundred dollars to overnight a new one (that's why I shoulda bought the Heath, in the first place), I recently moved the FSD to behind the front bumper. I wondered if a lot of recent wet weather had anything to do with causing this code to pop up. I'll see if it returns with the hurricane season.

Charley