Hi All,

I am at lost here. My initial issue is the fuel gauge is showing half tank while tank is full, and when I checked the OBD code it was P0462, so thought fuel pump (aka sending unit) went bad.

I have replaced the entire fuel pump twice. And then after more research people were saying that it could be the instrument cluster because it's a known issue for 2006 Altima's. So I bought a used one (close in mileage) and replaced it today, and it's the same issue. Checked fuel pump connector and all looks good. Checked voltage between the blue/green and ground and it's 11.4v DC while key is in ON (engine not started), and then if I jumper it to ground the fuel gauge is rising to full fine. Both black wire of fuel pump connector has solid ground as well. I have checked the original Nissan fuel pump resistance while floater is up and down and it's perfectly within range, so I thought it's not the fuel pump issue and so I went with cluster replacement.

When I put in the new (used one) cluster and checked the OBD code, I saw three codes: P0183, P0462 and P0463. I was able to clear all except code P0462.

I am totally at a loss. Please help!

Thanks!

The 11.4V on the float wire indicates the other end of the sensor doesn't have ground. Check for corrosion and/or burning of the female ground pin in the fuel pump connector. Nissans of all kinds are somewhat notorious for bad pumps drawing too much startup current and frying the ground pin.

PS - It's a common problem, so there are tons of the connectors on eBay or Amazon if that turns out to be the issue:

https://www.ebay.com/itm/153913763278

Hi VStar650CL,

Visually I checked connectors and see no burning or dis-coloration at all. I have changed fuel pump twice. Spoke with two nissan tech and both said to put genuine nissan pump which is like over $500 cost. I don't mind buying it but once you use it, you can't return it. Since you mentioned about connectors and pin itself. I am thinking about taking closer look using magnifying glass or try to remove one pin at a time using special tool. Any other suggestions?

Generally the color will clue you. Even though the slots into the cavity are tiny, when the ground pin overheats it will look different from the other 4, either black or simply not-shiny when inspected with a flashlight.

I'm with OE-parts-only for electronic stuff like crank sensors and MAF's, but not fuel pumps. There's no rocket-science in either the pump or the sender, and I've never noticed any big issues with reputable aftermarket brands. The only exception I make personally is models which don't have service covers and require dropping the tank, simply because a bum part will be a gigantic PITA in both cost and time. For those models I recommend my customers stick to OE.

PS - The front aligning-cover on the connector will simply pry loose to allow inspection of the female contacts. If you look at the pics in that eBay listing, the aligning cover is the white plastic part inserted into the face of the gray connector body. Prying up on the side of it with a small screwdriver or hook tool will pop it loose from the body.

I will popup that white cover tomorrow to see inside. While disconnecting sending unit connector, The voltage coming at pin is fine when I measured it and while key is ON and gauge is showing at F, and if I jump that pin to body of the car (ground, I used seat belt bolt), gauge is going down to E and I see gas lite turns on (telling that tank is empty) and I believe that's how it should be. But when I put connector back to pump and manually raise or lower floater, its only goes to F (floater at high) and then it goes to middle of gauge (floater is at lowest end) and its same result for both new pump and original nissan pump.