First question first. You can not use cruise control to keep steady speed. You must maintain steady speed using the gas pedal, strictly. The system needs to test the throttle position sensor. Without you depressing the gas pedal, it has no way of doing this. A variance of 3 miles per hour is acceptable. The driving pattern we indicate below to help get your Honda Odyssey's emission monitors ready is designed to be followed in the specific order presented. A Honda dealership may have more detailed specifics on exact required parameters for specific/individual drive cycles, but that information has not yet been made public. Honda, and many manufacturers alike, have designed their drive cycles (driving patterns) to be met automatically during routine driving. Most often, in a matter of a few days after having cleared the emission monitors for one reason or another, the vehicle completes its self-tests and marks the corresponding monitors as "Complete" or "Ready'.
Now as far as would could cause all the monitors to be ready accept the catalyst or CAT monitor, that question can only be answered after analyzing your Honda's freeze-frame and live data. Dozens of parameters are measured and must be met before the CAT monitor is set. Any variation in data i.e. voltage, frequency, which the computer sees as not normal will not allow the drive cycle to set the monitor.
We indicate the drive cycle pattern below which should make your Honda Odyssey ready for the smog test. Take extra caution when performing the drive cycle on public roadways. Perform the drive cycle at your own risk. If you feel you might not be able to perform the drive cycle safely, or obey all traffic laws, seek the assistance of a Honda repair center or certified smog check repair station which will be able to perform the drive cycle on a dynamometer and be utilizing specialized OBD II drive cycle readiness tools/scanner/computer.
Step for Setting Emission Monitors for Honda Odyssey
A. COLD START: Begin from Cold Start, and ignition in OFF position for at least 1 hour. Ensure your Honda Odyssey's fuel tank is between 1/4 and 3/4 full and engine coolant temperature is below 122°F and within 11°F of the ambient air temperature. Do not leave the key on prior to the cold start.
B. IDLE TIME: Start the engine (do not drive) and allow to idle for 2 1/2 minutes with the air conditioner on and rear defroster on. During this period the ECU will be running the Oxygen Sensor Heater self-test, Air Injection System Passive Air test, EVAP Purge "No Flow" test, Misfire Detection.
C. DRIVE: Turn off the air conditioner and rear defroster and begin driving. When possible, speed up to 55 mph. The ECU will now run self-tests on the Misfire Detection, Fuel Trim, and EVAP Purge Flow.
D. HOLD STEADY: Keep vehicle speed steady at 55 mph for three (3) minutes. During this time the Oxygen Sensor O2 response, Air Intrusive (AIS System), EGR Flow, Purge Valve, Misfire Detection, and Fuel Trim diagnostics will be performed.
E. DECELERATE: Slowly let off the accelerator pedal. Do not brake or shift in order to slow down. It is important to let your Odyssey coast gradually, slowing down to 20 mph. The ECU will once again self-test the EGR System, EVAP Purge System and Long Term Fuel Trims.
F. ACCELERATE: Accelerate, using 3/4 throttle, until 55-60 mph is reached. This will perform the same self tests as during the first acceleration step C.
G. HOLD STEADY: Hold steady speed once again. This time at 55mph for five minutes. During this time, in addition to running the self-tests as during the first HOLD STEADY step, the ECU will perform the catalyst monitor diagnostics. If the catalyst (Catalytic Converter) is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst,or in order to Complete the CAT Monitor.
H. DECELERATE: This will perform the same diagnostics as in Step E. Remember not to depress the brakes or shift gears during deceleration.
This should complete the drive cycle on your Honda Odyssey. To ensure all monitors are complete use a scan tool. We recommend completing this drive cycle twice in case in any step timing or speed was not achieved.
