Inspection Procedure 4

Fuel Gauge does not Work.

Fuel Gauge Circuit:

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 gauge unit the float moves up and down.
- The fuel gauge moves the needle by the circuit current.

TECHNICAL DESCRIPTION (COMMENT)
The cause is thought to be due to malfunction of the fuel gauge unit or combination meter.

TROUBLESHOOTING HINTS
- Malfunction of the 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 6.

STEP 2. Check the fuel gauge unit.

Check to see if the fuel gauge is normal.

Q: Is the fuel gauge unit normal?

YES: Go to Step 3.

NO: Replace the fuel gauge unit. The fuel gauge should work normally.

STEP 3. Measure at fuel gauge unit connector D-10 in order to the ground circuit to the fuel gauge unit.




1. Disconnect fuel gauge unit connector D-10, and measure at the wiring harness side.




2. Measure the resistance value between terminal 2 and ground.
- The measured value should be 2 Ohm or less.

Q: Does the measured resistance value correspond with this range?

YES: Go to Step 6.

NO: Go to Step 4.




STEP 4. Check fuel gauge unit connector D-10 for damage.

Q: Is fuel gauge unit connector D-10 in good condition?

YES: Go to Step 6.

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







STEP 5. Check the wiring harness between fuel gauge unit connector D-10 (terminal 2) and ground.

NOTE: Also check intermediate connector D-14. If intermediate connector D-14 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between fuel gauge unit connector D-10 (terminal 2) 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 fuel gauge unit connector D-10 and combination meter connector C-02 for damage.

Q: Are fuel gauge unit connector D-10 and combination meter connector C-02 in good condition?

YES: Go to Step 8.

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













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

NOTE: Also check intermediate connectors C-127 and D-14. If intermediate connector C-127 or D-14 are damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Are the wiring harness between fuel gauge unit connector D-10 (terminal 1) and combination meter connector C-02 (terminal 51) 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.