Test No. 18: Fuel Gauge Does Not Operate
- Check fuel gauge sending unit. See FUEL GAUGE SENDING UNIT under COMPONENT TESTS. If fuel gauge sending unit is okay, go to next step. If fuel gauge sending unit is defective, replace fuel gauge sending unit and recheck fuel gauge operation.
- Check wiring harness and electrical connectors between fuel gauge sending unit and body Electronic Control Unit (ECU). See WIRING DIAGRAMS in INSTRUMENT PANELS - CARS article. Body ECU is located on instrument panel junction block and contains 12-pin, 22-pin and 25 pin electrical connectors. See Figure. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary and recheck fuel gauge operation.
- Check combination meter on instrument cluster for problem which prevents operation of fuel gauge. See FUEL GAUGE under SYSTEM TESTS in INSTRUMENT PANELS - CARS article. If combination meter is okay, go to next step. If combination meter is defective, repair or replace components and recheck fuel gauge operation.
- Check body ECU for proper voltage and input signals. See BODY ELECTRONIC CONTROL UNIT under PIN VOLTAGE TESTS. If proper voltage and input signals exist, go to next step. If proper voltage and input signals do not exist, repair as necessary and recheck fuel gauge operation.
- Replace body ECU with a known-good body ECU and recheck fuel gauge operation. If fuel gauge operates properly, original body ECU was defective. If fuel gauge still does not operate properly, check wiring harness and electrical connectors for body ECU and fuel gauge sending unit for intermittent problem. See WIRING DIAGRAMS in INSTRUMENT PANELS - CARS article. Repair wiring harness or electrical connector as necessary.