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).
- Selector lever is in "D" range.
NOTE:
Remove all test equipment from vehicle and install all components and connectors that were removed or disconnected during testing.
Monitor takes about 35 minutes to complete. This cycle must be completed 2 times. Run monitor as shown. See Fig 1 . Perform steps as follows:
- Start engine.
- Accelerate to 55-60 MPH (89-97 km/h).
- Travel for 30 minutes or more while keeping the vehicle speed at 55-60 MPH (89-97 km/h). Carry out one gradual deceleration and acceleration returning to 55-60 MPH (89-97 km/h) within 120 seconds (during monitor).
- Return the vehicle to the shop and turn the ignition switch to LOCK position.
- Check for DTCs. If DTC P0171 or P0172 resets, return to appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .