Inspection Procedure 3

Fuel Gauge does not Work.

Part 1:

Part 2:

CIRCUIT OPERATION
- The ignition switch (IG1) circuit is the power source for the fuel gauge.
- The resistance value fluctuates causing the circuit current to fluctuate when the fuel level sensor the float moves up and down.
- The fuel gauge moves the needle by the circuit current.

TECHNICAL DESCRIPTION (COMMENT)
If the ignition switch (IG1) circuit is open, the gauge needle will not move at all. If the ground circuit is open, the gauge needle will move up to its extreme position.

TROUBLESHOOTING HINTS
- Malfunction of the fuel level sensor (fuel gauge unit)
- Malfunction of the combination meter (printed-circuit board or fuel gauge assembly)

DIAGNOSIS

Required Special Tool:
MB991223: Harness Set

STEP 1. Check with other meter.
Check to see that the speedometer, fuel gauge and water thermometer operate normally.

Q: Do all other meters operate?

YES Go to Step 2.

NO Refer to INSPECTION PROCEDURE 5.

STEP 2. Check fuel level sensor (sub) connector D-10 and fuel level sensor (main) connector D-12 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are fuel level sensor (sub) connector D-10 and fuel level sensor (main) connector D-12 in good condition?

YES: Go to Step 3.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. The fuel gauge should work normally.

STEP 3. Check the fuel level sensor (sub) and fuel level sensor (main).
Check to see that the fuel level sensor (sub) and fuel level sensor (main) are normal.

Q: Are fuel level sensor (sub) and fuel level sensor (main) normal?

YES: Go to Step 4.

NO: Replace fuel level sensor (sub) and fuel level sensor (main). The fuel gauge should work normally.

STEP 4. Check the ground circuit to the fuel level sensor (main). Measure the resistance at fuel level sensor (main) connector D-12.

1. Disconnect fuel level sensor (main) connector D-12 and measure the resistance available at the wiring harness side of the connector.

2. Measure the resistance value between terminal 1 and ground.
- The resistance should equal 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES: Go to Step 6.

NO: Go to Step 5.

STEP 5. Check the wiring harness between fuel level sensor (main) connector D-12 (terminal 1) and ground.

NOTE: Also check intermediate connector D-34 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector D-34 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between fuel level sensor (main) connector D-12 (terminal 1) and ground in good condition?

YES: There is no action to be taken.

NO: Repair the wiring harness. The fuel gauge should work normally.

STEP 6. Check combination meter connector C-02 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is combination meter connector C-02 in good condition?

YES: Go to Step 7.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. The fuel gauge should work normally.

STEP 7. Check the wiring harness between fuel level sensor (sub) connector D-10 (terminal 1) and combination meter connector C-02 (terminal 51).

NOTE: Also check intermediate connectors C-113 and D-34 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-113 or D-34 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between fuel level sensor (sub) connector D-10 (terminal 1) and combination meter connector C-02 (terminal 51) in good condition?

YES: Go to Step 8.

NO: Repair the wiring harness. The fuel gauge should work normally.

STEP 8. Check the wiring harness between fuel level sensor (sub) connector D-10 (terminal 2) and fuel level sensor (main) connector D-12 (terminal 2).

Q: Is the wiring harness between fuel level sensor (sub) connector D-10 (terminal 2) and fuel level sensor (main) connector D-12 (terminal 2) in good condition?

YES: Repair or replace the combination meter. The fuel gauge should work normally.

NO: Repair the wiring harness. The fuel gauge should work normally.