Xterra/PathFinder Fuel Gauge Erratic – P0463 Check Engine Light

11:00 am fuel pump, How To Auto Repair, Nissan
Summary: Automotive repair article covering a common problem related to Nissan Pathfinders and Xterras fuel gauge reading erratically. A check engine light may also be scanned with an OBD II code reader or scan tool related to a fault detected in the fuel gauge circuit (P0643 po463). Suggestions on how to diagnose, troubleshoot and save money on the repair. Repair article mentions tools used and has images.

A common issue with many Nissans has to do with an inaccurate fuel reading. The fuel needle on the gauge may bounce around before finally coming to a stop. Sometimes the fuel gauge may take an excessive amount of time to show “full” after filling up at the gas pump. Many times the CEL (Check Engine Light) or also known as SES (Service Engine Soon) warning will display on the dash. Most of the time the trouble code pulled will be a P0463, the definition of this fault is “fuel level sensor input high.”

Affected Vehicles
2005 Nissan Pathfinder LE 4.0L, 2006 Nissan Pathfinder SE Off-Road 4.0L, 2005 Nissan Xterra S 4.0L 2006 Nissan Xterra S 4.0L, 2006 Nissan Frontier LE 4.0L, 2007 Nissan Pathfinder LE 4.0L, 2006 Nissan Pathfinder LE 4.0L 2007 Nissan Pathfinder SE 4.0L. Others may also be affected.
Trouble Shooting
Use a multi meter to check the fuel level sensor ohms across the terminals of the fuel level sensor that match up with the brown wire and the black/yellow wire on the harness side. The specification should be close to 6.98 ohms with the float all the way up (which would normally mean the tank is full). The specs for an empty tank, float all the way down, should be 81.66 ohms. Refer to a service manual for more specific diagnostic instructions for your specific model. Use an online service manual for the most up to date info.
The fuel sending unit in the picture above is usually the problem.
 
If the contacts get worn and do not make a good connection the vehicles computer will set the P0463 fault code making the engine light come on. The fuel gauge will be inaccurate at least some of the time depending on where the float is and how good the contacts are at that position.
Save Money by Changing Just the Sender

The difference in price for just the sender as opposed to the price for the fuel pump and sending unit can be $150 or more. The fuel sending unit fails at a much higher rate than the fuel pump on this particular model. With that being said, it may be more logical to replace just the sending unit and NOT change the fuel pump. This of course is the truck owner’s decision which other factors will need to be considered as well. Like, how many miles are on the vehicle? How long does the present owner plan on keeping the vehicle? How much does a $150 bucks mean at this point in time? Of course changing the entire assembly could save a break-down if the old fuel pump is soon to fail. 

Doing the Repair on a lift by angling the tank.

Changing the Fuel Level Sensor

Vehicle lift or not, it’s best to have a mostly empty tank. If doing the repair on a vehicle lift, the tank does not necessarily have to be dropped completely. If doing this repair at home in the garage or driveway, the tank will most likely need to be removed completely. The reason is that the angle required to access the fuel pump/sending unit assembly will not be easy to obtain with the truck only a foot or so off the ground. Although a special fuel lock ring tool is available for purchase, many technicians use a screwdriver and a hammer to remove and install the lock ring. One word of caution: when re-installing the tank make sure the EVAP hose is placed back into the recessed portion of the molded gas tank. If it isn’t it can be crushed causing an evaporative incorrect flow trouble code.

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Related Links

Multimeters – Multi Meters for sale

Scan Tools – Code Readers

Car Repair Questions Page

On-Line Auto Repair Manuals

 

One Response
  1. Mike :

    Date: December 26, 2010 @ 1:03 am

    This is a common problem on 2005 and up Xterra’s. Nissan just recently extended the warranty on these sending units beyond the normal warranty period. Check with your dealer. As well, check out the condition of your radiator on the same truck. They also have had their warranty extended due to coolant leaking into the trans coolers.

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