Monitors, Trips, Drive Cycles and Readiness Codes
Readiness Code Resetting Procedure (Generic Drive Cycle)Readiness Monitors and Drive Cycles
"Readiness Monitors" are indicators that demonstrate whether or not emission system components are being monitored (checked) by the OBD-II system. If a monitor is set to "Ready" the monitor is checking its assigned component and, if no DTC's are present, the vehicle should pass an emissions test.
NOTE: If the appropriate number of Readiness Monitors (codes) are not flagged as "Ready", in most cases, the vehicle can not pass an emissions test. See State and Federal Laws.
The status of all readiness monitors is reset to "Not Ready":
Each time DTC's are cleared.
The battery is disconnected.
The ECM is disconnected.
The status of all readiness monitors is reset to "Ready":
After DTC's are cleared and the appropriate drive cycle(s) is successfully completed.
EPA Federal Test Procedure:
Manufacturers are required to validate monitors during the first 23 minutes (1372 seconds) of the Federal Test Procedure Drive Cycle.
EPA Urban Dynamometer Driving Schedule:
Completing the Drive Cycle successfully one (1) time should reset most drive cycle monitors to a "Ready" status. However, there are "two trip" monitors, which require that the drive cycle be successfully completed two (2) times, to achieve a "Ready" status. Furthermore, systems which use averaging, may require the drive cycle to be completed more than 2 times.
Verify the status of the readiness monitors with the appropriate function of your scan tool.
NOTE: Certain vehicles have known OBD-II Readiness issues. Please be sure to review TSB's for special circumstances and or exceptions to readiness monitor resetting procedures.
Before Beginning the Drive Cycle
Check the status of the Readiness Monitors, check for DTC's, correct faults, clear DTC's before beginning the Drive Cycle.
Begin Drive Cycle
The vehicle should be driven approximately 7.5 miles within a period of approx. 23 minutes (1372 seconds) from a cold start. However, due to manufacture variations, it is necessary to perform only as much of the Drive Cycle as is necessary to reset the required monitors to a "Ready" status. Operate the throttle smoothly to obtain best results. Do not shut the engine off during the drive cycle.
CAUTION: Obey all traffic laws and drive in a safe manner!
NOTE: Extreme driving conditioning such as very high/low temperatures, rough roads and high altitudes may prevent some monitors from attaining a "Ready" status.
All Monitors - Highway Drive Cycle
Notes 1. This drive cycle is designed to simulate highway driving.
2. When instructed, vary speed smoothly.
3. Also perform the All Monitors - Urban (City) Drive Cycle twice.
Conditions: Cold Start
Step 1 Idle 20 seconds. Accelerate gradually and drive at 20-25 mph for 1 minute, varying speed.
Step 2 Drive 25-31 mph within 35 seconds. Decelerate to 0 mph in 10 seconds. Idle for 40 seconds.
Step 3 Accelerate moderately. Drive at 20-25 mph for 20 seconds. Increase speed to 40-55 mph for 85 seconds, then decelerate to 0 mph over 50 seconds. Idle for 15 seconds.
Step 4 Gradually increase speed to 36 mph in 35 seconds. Decelerate to 0 mph in 15 seconds. Idle for 10 seconds.
Step 5 Accelerate to 30 mph and back to 0 mph within 25 seconds. Idle for 20 seconds.
Step 6 Accelerate to 36 mph in 20 seconds. Drive at 35 mph for 20 seconds. Decelerate to 0 mph in 15 seconds. Idle 5 seconds.
Step 7 Accelerate to 26 mph and decelerate to 0 within 40 seconds. Idle 15 seconds.
Step 8 Accelerate to 27 mph in 40 seconds. Decelerate to 0 mph in 8 seconds. Idle 25 seconds.
Step 9 Accelerate to 26 mph and decelerate to 0 mph in 35 seconds. Idle 15 seconds.
Step 10 Drive in stop and go traffic for 1 minute, reaching 25-30 mph twice, with no complete stops.
Step 11 Drive 20-30 mph for 2 minutes and stop. Vary speed. Drive 20-28 mph for 2 1/2 minutes at varying speeds. Stop. Idle for 30 seconds
Step 12 Accelerate to 28 mph and back to 0 in 50 seconds. Accelerate to 20 mph in 10 seconds, drive 20-27 mph for 20 seconds and decelerate to 0 in 10 seconds. Idle 15 seconds.
Step 13 Accelerate to 23 mph and back to 0 mph 20 seconds. Idle 10 seconds. Accelerate to 22 mph and back to 0 mph within 45 seconds. Idle for 10 seconds.
Step 14 Accelerate to 25 mph in 30 seconds. Drive at 23-28 mph for 25 seconds. Decelerate to 0 in less than 10 seconds.
Step 15 Idle for 25 seconds. Accelerate to 22 mph and back to 0 mph in 30 seconds.
All Monitors - Urban (City) Drive Cycle
Notes 1. This drive cycle is designed to simulate highway driving.
2. When instructed, vary speed smoothly.
3. Also perform the All Monitors - Highway Drive Cycle twice.
Step 1 Start the engine. Idle 20 seconds.
Step 2 Accelerate at part throttle to 30 mph. Cruise at 20-30 mph for 2 minutes. Stop the vehicle. Idle for 40 seconds.
Step 3 Accelerate at part throttle to 25 mph in 15 seconds. Cruise at 17-25 mph for 15 seconds. Accelerate to 40 mph. Cruise at 40-56 mph for 2 minutes. Decelerate to 0. Idle for 15 seconds
Step 4 Accelerate at part throttle to 28-36 mph for 25 seconds. Decelerate to 0 in 15 seconds. Idle for 6 seconds.
Step 5 Accelerate to 30 mph and back to 0 in 25 seconds. Idle for 20 seconds.
Step 6 Accelerate at part throttle to 35 mph; cruise at 35 mph for 30 seconds. Drive at 35 mph for 20 seconds. Decelerate to 0. Idle 6 seconds.
Step 7 Accelerate at part throttle to 25-26 mph and back to 0 within 40-50 seconds. Idle for 20-25 seconds. Repeat this step.
Step 8 Accelerate at part throttle to 26 mph and back to 0 mph in 30 seconds. Idle 15 seconds.
Step 9 Accelerate at part throttle to 23 mph. Drive in a stop and go manner from 0-28 mph for 70 seconds. Accelerate at part throttle to 33 mph. Cruise between 25-35 mph, varying the speed smoothly.
Step 10 Stop and accelerate gradually to 28 mph. Cruise at 20-28 mph for 60 seconds. Idle for 30 seconds.
Step 11 Drive Drive in a stop and go manner for between 17-27 mph for 1 1/2 minutes. Idle for 15 seconds
Step 12 Accelerate to 28 mph and back to 0 in 50 seconds. Accelerate to 20 mph in 10 seconds, drive 20-27 mph for 20 seconds and decelerate to 0 in 10 seconds. Idle 15 seconds.
Step 13 Accelerate from 0-23 mph and back to 0 mph 20 seconds. Idle for 10 seconds.
Step 14 Accelerate at part throttle. Cruise at 20-30 mph for 60 seconds. Idle for 25 seconds.
Step 15 Accelerate steadily to 22 mph and back to 0 in 35 seconds.
NOTE: Remember, clearing DTC's or interrupting power to the ECM after the readiness monitors have been reset to "Ready" will require that the Drive Cycle be repeated.
Completing the Drive Cycle successfully one (1) time should reset most drive cycle monitors to a "Ready" status. However, there are "two trip" monitors, which require that the drive cycle be successfully completed two (2) times, to achieve a "Ready" status. Furthermore, systems which use averaging, may require the drive cycle to be completed more than 2 times. It is necessary to perform only as much of the Drive Cycle as is necessary to reset the required monitors to a "Ready" status.
End Drive Cycle