EGR Monitor

This monitor applies to DTC P0401. Following conditions must be met during the test:

• Engine coolant temperature must be 176°F (80°C) or more.
• Atmospheric temperature is 41°F (5°C) or more.
• Selector lever is in "D" range.
• A/C switch is in OFF position.

Monitor takes about 10 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 quickly accelerate to 35-40 MPH.
4. Keep speed constant at 35-40 MPH for 20 seconds or more (4th gear on M/T).
5. Decelerate by closing throttle fully allowing engine speed to drop from 2000-3000 RPM to about 900 RPM. DO NOT apply brakes. DO NOT turn steering wheel or operate light switch during this time (this is when monitor runs).
6. Accelerate to 35-40 MPH, then hold speed constant for 20 seconds or more. Repeat steps  4 and  5 , seven more times.
7. Return vehicle to shop and turn ignition off.

Fig 1: Running EGR Monitor

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.