Readiness Monitor Drive Pattern
READINESS MONITOR DRIVE PATTERN1. PURPOSE OF THE READINESS TESTS
- The On-Board Diagnostic (OBD II) system is designed to monitor the performance of emission-related components, and report any detected abnormalities with Diagnostic Trouble Codes (DTCs). Since various components need to be monitored during different driving conditions, the OBD II system is designed to run separate monitoring programs called readiness monitors.
- The hand-held tester's software must be version 9.0 or newer to view the readiness monitor status. From the "ENHANCED OBD II" menu, select "MONITOR STATUS" to view the readiness monitor status.
- A generic OBD II scan tool can also be used to view the readiness monitor status.
- When the readiness monitor status reads "complete", the necessary conditions have been met for running performance tests for that readiness monitor.
HINT: Many state Inspection and Maintenance (I/M) programs require a vehicle's readiness monitor status to show "complete".
- The Readiness Monitor will be reset to "incomplete" if:
- The ECM has lost battery power or blown a fuse.
- DTCs have been cleared.
- The conditions for running the Readiness Monitor have not been met.
- If the readiness monitor status shows "incomplete", follow the appropriate readiness monitor drive pattern to change the status to "complete".
CAUTION: Strictly observe of posted speed limits, traffic laws, and road conditions when performing these drive patterns.
NOTE:
The following drive patterns are the fastest method of completing all the requirements necessary for making the readiness monitor status read "complete".
If forced to momentarily stop a drive pattern due to traffic or other factors, the drive pattern can be resumed. Upon completion of the drive pattern, in most cases, the readiness monitor status will change to "complete".
Sudden changes in vehicle load and speed, such as driving up and down hills and / or sudden acceleration, hinder readiness monitor completion.
2. CATALYST MONITOR
a. Preconditions
The monitor will not run unless:
- MIL is OFF.
- Engine Coolant Temperature (ECT) is 75°C (167°F) or greater.
- Intake Air Temperature (IAT) is -10°C (14°F) or greater.
NOTE: The readiness test can be completed in cold ambient condition (less than -10°C (14°F)) if the following is performed: 1) finish the first drive pattern, 2)turn the ignition switch OFF and then ON again, and 3) repeat the drive pattern a second time.
b. Drive Pattern
1. Connect the OBD II scan tool to the DLC3 to check monitor status and preconditions.
2. Drive the vehicle at 40 to 55 mph (64 to 88 km/h) for approximately for 3 minutes.
NOTE: Drive with smooth throttle operation and avoid sudden acceleration.
If IAT is less than 10°C (50°F) when engine was started, drive the vehicle at 40 to 55 mph (64 to 88 km/h) for additional 4 minutes.
3. Drive the vehicle at 35 to 45 mph (56 to 72 km/h) for approximately 7 minutes.
NOTE: Drive with smooth throttle operation and avoid sudden deceleration as much as possible with the throttle fully closed.
4. If readiness status does not switch to complete, make sure that the preconditions are met and the that the ignition switch is turned OFF. Then repeat steps (2) and (3).
5. Release pressure in the fuel tank by removing and then reinstalling the fuel tank cap.
6. Start the engine and immediately begin driving as directed.
3. EVAP SYSTEM MONITOR
NOTE: A cold soak must be performed prior to conducting the drive pattern to complete the internal pressure readiness monitor.
a. Cold Soak Preconditions
The monitor will not run unless:
- MIL is OFF
- Fuel level is approximately 1/2 to 3/4
- Altitude is 8,000 ft (2,400 m) or less
b. Cold Soak Procedure
Let the vehicle cold soak for 8 hours or until the difference between IAT and ECT becomes less than 7°C (13°F)
HINT:
Examples:
- Scenario 1
ECT = 24°C (75°F)
IAT = 16°C (60°F)
Difference between ECT and IAT is 8°C (15°F)
-> The monitor will not run because difference between ECT and IAT is greater than 7°C (13°F)
- Scenario 2
ECT = 21°C (70°F)
IAT = 20°C (68°F)
Difference between ECT and IAT is 1°C (2°F)
-> The monitor will run because difference between ECT and IAT is less than 7°C (13°F)
c. Preconditions
The monitor will not run unless:
- MIL is OFF
- Fuel level is approximately 1/2 to 3/4
- Altitude is 8,000 feet (2,400 m) or less
- Engine Coolant Temperature (ECT) is between 4.4°C and 35°C (40°F and 95°F)
- Intake Air Temperature (IAT) is between 4.4°C and 35°C (40°F and 95°F)
- Cold Soak Procedure has been completed
- Before starting the engine, the difference between ECT and IAT must be less than 7°C (13°F)
HINT:
Examples:
- Scenario 1
ECT = 24°C (75°F)
IAT = 16°C (60°F)
Difference between ECT and IAT is 8°C (15°F)
-> The monitor will not run because the difference between ECT and IAT is higher than 7°C (13°F)
- Scenario 2
ECT = 21°C (70°F)
IAT = 20°C (68°F)
Difference between ECT and IAT is 1°C (2°F)
-> The monitor will run because the difference between ECT and IAT is less than 7°C (13°F)
The readiness test can be completed in cold ambient conditions (less than 4.4°C (40°F)) and/or at high altitudes (8,000 ft (2,400 m)) if the following is performed: 1) finish the first drive pattern, 2) turn the ignition switch OFF and then ON again, and 3) repeat the drive pattern a second time.
d. Drive Pattern
1. Connect the OBD II scan tool to the DLC3 to check monitor status and preconditions (refer to step (a)).
2. Release pressure in fuel tank by removing the fuel tank cap and then reinstalling it.
3. Start the engine and allow it to idle until ECT becomes 75°C (167°F) or higher.
4. Run the engine at 3,000 rpm for about 10 seconds.
5. Allow the engine to idle with the A/C ON (to create a slight electrical load) for 15 to 50 minutes.
NOTE:
If the vehicle is not equipped with A/C, create an electrical load on the engine by doing the following:
- Securely set the parking brake.
- Block the drive wheels with wheel chocks.
- Allow the vehicle to idle in drive for 15 to 50 minutes.
4. OXYGEN SENSOR MONITOR
a. Preconditions
The monitor will not run unless:
- MIL is OFF
b. Drive Pattern
1. Connect the OBD II scan tool to DLC3 to check monitor status and preconditions (refer to step "a").
2. Start the engine and allow it to idle for 2 minutes or more.
3. Drive the vehicle at 25 mph (40 km/h) or more for at least 50 seconds.
4. Stop the vehicle and allow the engine to idle for 40 seconds or more.
5. Perform steps (3) and (4) ten times.
6. Check the status of the readiness monitor on the scan tool display. If readiness status did not switch to complete, ensure preconditions are met, turn the ignition off and then repeat steps (1) and (5).
5. OXYGEN SENSOR HEATER MONITOR
a. Preconditions
The monitor will not run unless:
- MIL is OFF
b. Drive Pattern
1. Connect the OBD II scan tool to the DLC3 to check monitor status and preconditions (refer to step (a)).
2. Start the engine and allow it to idle for 500 seconds or more.
3. Drive the vehicle at 25 mph (40 km/h) or more for at least 2 minutes.
4. Check the status of the readiness monitor on the scan tool display. If readiness status did not switch to complete, ensure the preconditions are met, turn the ignition switch OFF, and then repeat steps (2) and (3).