If your Honda failed a smog test due to “not ready” monitors, an OBDII drive cycle can help. This procedure enables your Honda’s diagnostic system to run self-tests and set readiness monitors, vital for passing emissions inspections. This specific drive cycle is designed for Honda vehicles and requires precise execution.
Performing the OBDII Drive Cycle on Your Honda
1. Cold Start and Initial Idle
Begin with a cold start: coolant temperature below 122°F (50°C), air and coolant sensors within 11°F (6°C). Do not turn the ignition on before starting, to allow oxygen sensor diagnostics. Idle in drive for 2.5 minutes with AC and rear defrost on. This checks oxygen sensor heaters, air pump, and EVAP purge.
2. Acceleration and Steady Speed
Turn off AC/defrost. Accelerate to 55 mph (88 km/h) at half throttle. This initiates checks for misfire, fuel trim, and canister purge. Hold 55 mph for 3 minutes, monitoring EGR, air pump, O2 sensors, and canister purge.
3. Deceleration
Coast down to 20 mph (32 km/h) without braking/clutch, checking EGR and purge functions.
4. Re-acceleration and Steady Speed
Accelerate to 55-60 mph (88-96 km/h) at half throttle, re-checking misfire, fuel trim, and purge.
5. Extended Steady Speed
Maintain 55-60 mph for 5 minutes. Monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors, and purge.
6. Final Deceleration and Stop
Decelerate to a stop without braking, for a final EGR and canister purge check.
Conclusion: Completing this OBDII drive cycle for your Honda allows full assessment of emissions components. Successful execution should set readiness monitors, preparing your Honda to pass its smog test.
