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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 291 (Engine Controls - Trouble Shooting - No Codes) >> Symptoms >> Restricted Exhaust >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify the customers concern. Check the vehicle under the same conditions that the customer reported to verify the system is operating as designed. 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 no, go to SYMPTOMS  .
  3. Is the system equipped with dual exhaust? If yes, go to DIAGNOSTIC AIDS  . If no, go to next step.
  4. Remove the HO2S 1, in front of the catalytic converter. Install the Exhaust Back Pressure Gauge (J 35314-A) in place of the HO2S 1. Start the engine. Increase and monitor the engine speed at 2500 RPM. Observe the exhaust system back pressure reading on the gauge. Does the reading exceed 1.25 psi (9 kPa)? If yes, go to next step. If no, go to step  8 .
  5. Turn the engine OFF and turn ignition switch to LOCK position. Remove the exhaust back pressure gauge. Re-install the HO2S 1. Remove the post-catalyst HO2S 2. Install the exhaust back pressure gauge in place of the HO2S 2. Start the engine. Increase and monitor the engine speed at 2500 RPM. Observe the exhaust system back pressure reading on the gauge. Does the reading exceed 1.25 psi (9 kPa)? If yes, go to next step. If no, go to step  7 .
  6. Check the exhaust system for damage in the exhaust pipe, debris in the exhaust pipe, muffler or resonator internal failure or two-layer exhaust pipe separation. Repair as necessary. After repair, go to step  8 .
  7. Replace the catalytic converter. After repair, go to next step.
  8. Remove the exhaust back pressure gauge. Reinstall the HO2S 2 (post converter). Clear any codes using a scan tool. Road test the vehicle to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step  2 .
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