How To: Fix erratic fuel level reading on digital dash

This How To is for people with digital dash whose fuel level gauge has erratic or erronious readings. This erratic reading will also affect Distance to Empty (DTE) and in some cases Bitching Betty saying "Warning, Low Fuel".

This How To will also work for analog dash cars.

Nissan has an updated part for the fuel level sending units of the Z31. The original units were of a canister or barrel style system with an internally guided float. Over the years, the potentiometer portion of the sending units gets corroded and wildly affects the resistance of the unit, thereby giving inaccurate readings.


For digital dash cars you will need to order this part from your Nissan place of choice.
25060-17P75


For analog dash cars you will need to order this part from your Nissan place of choice.
25060-17P65
NOTE Analog dash cars may not have the silver box. It has been reported that some digital dash cars do not have the silver box. The new kit will include the silver box for digital dash cars and includes the integral jumper harness. If your car does not originally have the silver box and the new kit has one, install it as shown in the steps below.

1 First step is to disconnect the negative battery terminal.

2 Open the hatch and lift up the rear carpet. Then remove the tool kit and fold back the foam padding.

3 You will see a big round plate with 2 Phillips screws. Remove these and lift up round plate.

4 The sending unit is directly under the plate. Follow the black wire harness that comes out of the left side of the round plate to where the connectors are and disconnect the blue and white connectors. Push the harness grommet thru the plate and feed the harness thru. Then remove the six 8mm bolts. Take a set of pliers and grab the top of the sending unit and pull straight up with a slight twisting motion and set on the ground.


5 Locate the silver box and remove the Phillips screw holding the box and the Phillips screw holding the ground wire.



6 Now set the old and new components on the ground and compare.
Old on left, new on right.



As you see, the sending units are very different. Do not be alarmed. The new design is far more superior than the original design. The silver boxes on the other hand are the same (at least in my case). Replace the silver box regardless.

7 Now install the new sending unit very very carefully. DO NOT BEND THE FLOAT ARMS!!! If you do, the accuracy of the sending unit will be affected. It may take a few tries to get it in the hole. Do not force it. Once you get it in, make sure the float arms are pointing to the left side of the car. It will look like this when oriented correctly, note wire colors. Then feed the new white harness thru the plate hole and install the grommet to the plate. Reinstall the plate with the 2 flat headed Phillips screws.


8 Now install new silver black box. Be sure to correctly put the ground wire eyelet back on like original. Connect the connectors. They will only go in one way, so don't worry.



9 Now reinstall the foam padding, tool kit, and rear carpet and shut the hatch.

10 Reconnect the negative battery terminal. Turn on car and make sure the gauge works properly. Go drive and have fun.