Fuel Trim Monitor

2001 Mitsubishi Mirage DE, StandardSECTION Fuel Trim Monitor

This monitor applies to DTCs P0171 and P0172. Following conditions must be met during the test:

  • Engine coolant temperature is 176-207°F (80-97°C).
  • Atmospheric temperature is 14-140°F (-10-60°C).
  • On A/T, selector lever is in "D" range.

Monitor takes about 35 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. After engine is completely warmed up, turn ignition off.
  3. Start engine and accelerate to 55-60 MPH.
  4. Drive at 55-60 MPH for 30 minutes or more. During this period DO NOT drive at constant speed for more than 120 seconds. Carry out gradual deceleration and acceleration within every 120 second time frame. On M/T, use 5th gear.
  5. Return vehicle to shop and turn ignition off.

Fig 1: Running Fuel Trim Monitor
G99C08399Courtesy 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:

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