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Home >> Saturn >> 2003 >> L300 >> Repair and Diagnosis >> Engine Performance >> System >> Troubleshooting - No Codes >> Symptoms >> Restricted Exhaust >> Test Procedure
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Test Procedure

  1. Did you verify the customers complaint? If yes, go to next step.
  2. Did you review the exhaust symptoms diagnostic information and perform the necessary inspections? If yes, go to next step. If not, check for any exhaust leaks.
  3. Remove the Heated Oxygen Sensor (HO2S) that is in front of and closest to the catalytic converter. See HEATED OXYGEN SENSOR under SENSORS & SWITCHES in REMOVAL & INSTALLATION - SATURN "L" SERIES article. Install the Gauge Bar Set or Exhaust Back Pressure Gauge in place of the HO2S sensor. Start the engine. Increase and monitor the engine speed at 2000 RPM. Observe the exhaust system back pressure reading on the gauge. If reading exceeds 2 psi (14 kPa), go to next step. If reading does not exceed 2 psi (14 kPa), go to step  7 .
  4. Turn engine OFF and place ignition in the lock position. Remove the Gauge Bar Set or Exhaust Back Pressure Gauge. Install the HO2S sensor. Remove the post-catalytst HO2S sensor. See HEATED OXYGEN SENSOR under SENSORS & SWITCHES in REMOVAL & INSTALLATION - SATURN "L" SERIES article. Install the Gauge Bar Set or Exhaust Back Pressure Gauge in place of the post HO2S sensor. Start the engine. Increase and monitor the engine speed at 2000 RPM. Observe the Exhaust System Back Pressure reading on the gauge. If reading exceeds 2 psi (14 kPa), go to next step. If reading does not exceed 2 psi (14 kPa), go to step  6 .
  5. Inspect the exhaust system for the following conditions:
    • Damage in the exhaust pipe.
    • Debris in the exhaust pipe.
    • Muffler or resonator internal failure.
    • A 2-layer exhaust pipe separation.

    Did you find and correct the condition? If yes, go to step  7 .

  6. Replace the catalytic converter. Did you find and correct the condition? If yes, go to next step.
  7. Remove the Gauge Bar Set or Exhaust Back Pressure Gauge. Install the HO2S sensor. Clear any codes. Road test the vehicle in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step  2 .
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