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Home >> Isuzu >> 2003 >> Ascender 5.3 P, RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing - 5.3L >> Fuel Systems >> Fuel Composition Sensor >> Diagnostic Procedures
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Diagnostic Procedures

  1. Test fuel composition using the Fuel Composition Tester (J-44175) and instruction manual. Record the frequency from the special tool test. Compare the special tool test frequency and the Fuel Comp. Sensor Frequency parameter on scan tool. Is the difference between the 2 frequencies less than 12 Hz? If yes, go to next step. If yes, go to step  3.
  2. Clean fuel system. Refer to FUEL SYSTEM CLEANING . Replace fuel filter. After repairs, go to step  4.
  3. Replace the fuel composition sensor, located near fuel filter. After replacing sensor, go to next step.
  4. Clear any DTCs with scan tool. Start engine. Operate vehicle in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to next step.
  5. Observe the DTC Info with scan tool. Are there any DTCs that have not been diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - ASCENDER 5.3L article. If no, system is okay.
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