LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 725 (Emission System) >> Warm-Up Three-Way Catalytic Converter (WU-TWC) Inspection >> Except for California Emission Regulation Applicable Models

Except for California Emission Regulation Applicable Models

WARNING: This page is about a different car, the 2004 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
  • Make sure that no HO2S DTCs have been detected. If detected, this inspection is not applicable for WU-TWC inspection.
  1. Connect the WDS or equivalent and monitor PIDs as following.
    • Monitor the WU-TWC using O2S11 PID for upstream HO2S and O2S12 PID for downstream HO2S.
  2. Monitor the appropriate PIDs.
  3. Drive the vehicle for 10 min  at 65-96 km/h {40-60 mph}  to allow the front catalytic converter to reach operating temperature.
  4. Stop the vehicle and leave it in a safe place.
  5. Idle the engine.
  6. Record PIDs for 1 min. 
  7. Select the appropriate PIDs and read the graph.
  8. Count the number of times (inversions) that the upstream HO2S graph line actually crosses the 0.5 V  line.
  9. Count the number of times (inversions) that the downstream HO2S graph line actually crosses the 0.5 V  line.
    NOTE:
    • Do not count the number of peaks. Refer to the graph.
    Fig 1: Catalytic Converter Inspection Graph
    G00973074Courtesy of MAZDA MOTORS CORP.
  10. Using the following equation, calculate the value of ratio.
    1. Equation RATIO = Upstream HO2S inversion / downstream HO2S inversion 
    • If the ratio is 1.5  or more or there is no downstream HO2S inversion, the WU-TWC is functioning properly.
    • If the ratio is less than 1.5,  the WU-TWC is not functioning properly. Replace the WU-TWC.
scientia non olet · About LEMON Manuals