FUEL LEVEL SENSOR CIRCUIT
Diagnostic Aids
Check for poor connection, rubbed-through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Using scan tool, monitor fuel level display while moving connectors and harness related to fuel sensor. Change in display will indicate problem area.
Diagnostic Procedure
1. Perform On-Board Diagnostic II (OBD-II) System Check. After performing OBD-II system check, go to next step.
2. Disconnect fuel level sensor harness connector. Turn ignition on. Using a voltmeter, measure voltage between sensor harness positive and sensor ground terminals. If reading is 5 volts, go to step 6. If reading is not as specified, go to next step.
3. Using DVOM, backprobe between ground and fuel level sensor 5-volt reference circuit at PCM harness connector. If reading is 5 volts, go to next step. If reading is not as specified, replace and reprogram PCM. Retest system.
4. Measure voltage between ground and fuel level sensor 5-volt reference circuit at sensor. If reading is 5 volts, go to next step. If reading is not as specified, go to next step.
5. Check for open or short to ground on 5-volt reference circuit between fuel level sensor and PCM. Repair as necessary. Retest system.
6. Remove fuel level sensor from fuel tank. Ensure sensor arm moves freely. Check wiring for an intermittent open circuit. Replace as necessary. If fuel level sensor tests okay, replace and reprogram PCM. Retest system.
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Wednesday, November 24th, 2010 AT 7:40 PM