Ford · Lincoln · Mercury
FORD OBD-II
DRIVE CYCLE GUIDE
What Ford owners should know about readiness checks, cold-soak requirements, highway and city operation, and model-year differences.
Drive cycle at a glance
Key-off soak
At least 8 hours
Highway
15 minutes steady
Stop-and-go
20 minutes
Idle periods
4 × 30 seconds
FORD READINESS BASICS
Ford procedures change by model and year, but many owner manuals describe a combination of a long key-off period, steady highway driving, and stop-and-go operation. A complete check can take several days of normal driving.
Quick Ford readiness check
On many Ford vehicles with a keyed ignition, switch the key to ON for about 15 seconds without cranking. If the Service Engine Soon light flashes eight times, the OBD-II system is not ready. If it remains steadily illuminated during the bulb check, the monitors are reported ready. Confirm with a scan tool because procedures can differ.
Common newer-Ford pattern
- Leave the vehicle off for at least eight hours when a cold soak is needed.
- Start the engine and allow it to reach normal operating temperature.
- Drive steadily on an expressway or highway for about 15 minutes.
- Follow with approximately 20 minutes of stop-and-go driving.
- Include at least four idle periods of about 30 seconds.
- Do not shut the engine off between starting and completing the route.
Older Ford example
Some older Ford manuals use a more structured sequence: reach operating temperature, idle for at least 80 seconds, accelerate at part throttle to about 45 mph, maintain a steady cruise, then complete lower-speed city driving with several stops. Treat this only as an older example—not a universal Ford procedure.
What commonly prevents completion
- A cold-soak requirement was not met.
- The battery or PCM memory was recently reset.
- The fuel level or ambient temperature blocks EVAP.
- Pending faults prevent catalyst, oxygen-sensor, EGR, or EVAP testing.
- Certain Ford calibrations or diesel aftertreatment repairs require special procedures.
Diesel note: Some Ford diesel exhaust-gas-sensor strategies after DOC or DPF replacement have documented degreening periods measured in thousands of miles. That special situation is not normal for every diesel.
STILL NOT READY?
Bring the year, make, model, engine, fuel type, and a list of the incomplete monitors. The Smog Dawg can help you understand what the vehicle is reporting and what should happen next.