Catalytic Converter Monitor

2007 Mitsubishi Endeavor SE, FWDSECTION Catalytic Converter Monitor

This monitor applies to DTCs P0421 and P0431. Following conditions must be met during the test:

  • Atmospheric temperature is 14Β°F (-10Β°C) or more.
  • A/C switch is in OFF position.
  • Selector lever is in "D" range.

Monitor takes about 20 minutes to complete. To run monitor, use illustration. See Fig 1. Perform steps as follows:

  1. Remove all test equipment from vehicle and install all components and connectors that were removed or disconnected during testing.
  2. Start engine.
  3. Accelerate to 45 MPH.
  4. Travel 5 minutes or more while keeping speed at 45-60 MPH (5th gear on M/T).
  5. Fully close throttle and decelerate to 35-40 MPH.
  6. While keeping accelerator pedal opening degree constant (4th gear on M/T), keep speed at 35-40 MPH for 90 seconds or more (this is when monitor runs).
  7. Fully close throttle and decelerate for 10 seconds. Then, quickly accelerate until speed is 35-40 MPH. Then repeat steps Β 5 and Β 6 five more times.
  8. Return vehicle to shop and turn ignition off.
Fig 1: Running Catalytic Converter Monitor
G99F52600Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.