Fuel Gauge Sending Unit Test

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: For the fuel gauge system circuit diagram, refer to the Gauges Circuit Diagram (see CIRCUIT DIAGRAM ).

Check the No. 21 METER (7.5 A) fuse in the under-dash fuse/relay box before testing.
Check for body electrical system DTCs (see GENERAL TROUBLESHOOTING INFORMATION ).
- If no DTCs are found, go to step 3.
- If DTC B1175 (see DTC B1175: FUEL LEVEL SENSOR (FUEL GAUGE SENDING UNIT) CIRCUIT OPEN ) or B1176 (see DTC B1176: FUEL LEVEL SENSOR (FUEL GAUGE SENDING UNIT) CIRCUIT SHORT ) is indicated, go to the indicated DTC'S TROUBLESHOOTING .
Turn the ignition switch to LOCK (0).
Remove the second row seat (see SEAT CUSHION BLOWER MOTOR ).
Remove the access panel (A) from the floor.

Fig 1: Identifying Fuel Tank Unit 4P Connector, Access Panel And Bolts
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Disconnect the fuel tank unit 4P connector (B).
Measure the voltage between fuel tank unit 4P connector terminals No. 1 and No. 3 with the ignition switch to ON (II). There should be battery voltage.
- If the voltage is OK, go to step 8.
- If the voltage is not as specified, check for:
  - a short in the ORN wire to ground.
  - an open in the ORN or LT GRN wire.
    
    Fig 2: Measuring Voltage Between Fuel Tank Unit 4P Connector Terminals No. 1 And No. 3
    Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to LOCK (0).
Remove the fuel tank unit from the fuel tank (see FUEL TANK UNIT REMOVAL AND INSTALLATION ).

Measure the resistance between fuel tank unit 4P connector terminals No. 1 and No. 3 with the float at E (EMPTY), LOW (LOW FUEL INDICATOR), 1/2 (HALF FULL), and F (FULL) positions.

If you do not get the following readings, replace the fuel gauge sending unit (see FUEL PUMP/FUEL GAUGE SENDING UNIT REPLACEMENT ).

Float Position	F 214.2 mm (8.4 in)	1/2 149.4 mm (5.9 in)	LOW 50.8 mm (2.0 in)	E 19.1 mm (0.8 in)
Resistance (Ω)	19 to 21	203.3 to 213.3	516.4 to 629	772 to 788

Fig 3: Measuring Resistance Between Fuel Tank Unit 4P Connector Terminals No. 1 And No. 3

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Reconnect the fuel tank unit 4P connector.
Remove the No. 7 BACK UP (10 A) fuse from the under-dash fuse/relay box for at least 10 seconds, then reinstall it.
Turn the ignition switch to ON (II).
Check that the pointer of the fuel gauge indicates F with the float at F.
- If the pointer of the fuel gauge does not indicate F, replace the gauge control module (see GAUGE CONTROL MODULE REPLACEMENT ).
- If the gauge is OK, the test is complete.
NOTE:
- The pointer of the fuel gauge returns to the bottom of the gauge dial when the ignition switch is in ACC (I) and LOCK (0), regardless of the fuel level.
- Remove the No. 7 BACK UP (10 A) fuse from the under-dash fuse/relay box for at least 10 seconds after completing troubleshooting, otherwise it may take up to 20 minutes for the fuel gauge to indicate the correct fuel level.