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DTC P1402 (FLVL) - Fuel Level Sensor Circuit Malfunction

  1. Ensure speedometer and tachometer is operating normally. Turn ignition off. Remove combination meter. Disconnect harness connector from combination meter. Check resistance between combination meter harness connector terminal No. 15 and chassis ground. See appropriate wiring diagram in WIRING DIAGRAMS article. If resistance is less than 5 ohms, replace combination meter. If resistance is 5 ohms or greater, go to next step.
  2. Check for open in circuit between combination meter and grounding terminal. Repair as necessary. If circuit is okay, go to next step.
  3. Turn ignition on, with engine off. Using DVOM connected to chassis ground, backprobe ECM harness connector terminal No. 27. If voltage reading is 4.75 volts or greater, go to step 5). If voltage reading is less than .12 volt, go to step 9). If voltage reading is less than 4.75 volts, but greater than .12 volt, go to next step.
  4. Connect SSM. Select SSM function mode F45 to check fuel level sensor output signal. Wiggle ECM harness connector while monitoring SSM. If value changes to less than .12 volt, check for poor terminal contact at ECM harness connector. If value does not change when wiggling ECM harness connector, problem is intermittent. Check for poor terminal contact at fuel pump, combination meter, ECM or coupling connector.
  5. Turn ignition off. Remove access cover to fuel tank located in luggage compartment. Disconnect fuel pump harness connector. Check resistance between fuel pump harness connector terminals No. 1 and 4. If resistance is 100 ohms or less, go to next step. If resistance is greater than 100 ohms, replace fuel sending unit.
  6. Check resistance between fuel pump harness connector terminal No. 1 and chassis ground. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, check for open in harness between fuel pump harness connector and chassis ground.
  7. Turn ignition on. Check voltage between fuel pump harness connector terminal No. 4 and chassis ground. If voltage reading is greater than one volt, go to next step. If voltage reading is one volt or less, check for open in harness between fuel pump harness connector and wiring harness junction. Also, check for poor terminal contact at fuel pump harness connector or coupling.
  8. Turn ignition off. Disconnect ECM harness connector. Turn ignition on. Check voltage between ECM harness connector terminal No. 27 and chassis ground. If voltage reading is one volt or less, check for open in circuit between ECM harness connector and wiring junction to fuel pump harness. If voltage reading is greater than one volt, check for poor terminal contact at fuel pump connector or ECM connector.
  9. Turn ignition off. Remove fuel pump access cover located in luggage compartment. Disconnect fuel pump harness connector. Check resistance between fuel pump harness connector terminal No. 4 and chassis ground. See appropriate wiring diagram in WIRING DIAGRAMS article. If resistance is 10 ohms or less, go to next step. If resistance is greater than 10 ohms, go to step 14).
  10. Disconnect wiring harness junction connector to fuel tank harness connector. Check resistance between fuel tank harness connector terminal No. 4 and chassis ground. If resistance is 10 ohms or less, check for short in circuit to fuel tank harness connector. If resistance is greater than 10 ohms, go to next step.
  11. Disconnect wiring harness junction connector to combination meter harness connector. Check resistance between rear wiring harness junction connector terminal No. 2 and chassis ground. If resistance is 10 ohms or less, go to next step. If resistance is greater than 10 ohms, check for short in circuit to combination meter.
  12. Disconnect rear wiring harness junction connector to bulkhead wiring harness connector. Check resistance between rear wiring harness connector terminal No. 4 and chassis ground. If resistance is 10 ohms or less, check for short in circuit to rear wiring harness. If resistance is greater than 10 ohms, go to next step.
  13. Disconnect bulkhead wiring harness connector and engine wiring harness connector. Check resistance between bulkhead wiring harness connector terminal No. 4 and chassis ground. If resistance is 10 ohms or less, check for short in circuit to bulkhead wiring harness. If resistance is greater than 10 ohms, check for short in circuit to engine wiring harness.
  14. Reconnect fuel pump harness connector. Remove combination meter. Disconnect harness connector from combination meter. Check resistance between combination meter harness connector terminal No. 14 and chassis ground. If resistance is 200 ohms or less, go to next step. If resistance is greater than 200 ohms, check for open in harness between combination meter connector and junction connector on rear wiring harness.
  15. Disconnect speedometer cable from combination meter and remove combination meter. Check if fuel gauge mounting screws are tight. Tighten screws. If screws are tight, check if printed circuit board has heat or burn damage. If damaged, replace printed circuit board. If printed circuit board is okay, replace fuel gauge assembly.
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