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STEPS TO PASSING

*AFTER CODE CLEARING

1. Complete multiple cold-start warm-up cycles

  • Restart your engine after it has entirely cooled (ideally overnight or after a few hours off).

  • Let it idle or drive briefly until it reaches normal operating temperature.

  • Turn it off and allow it to cool again.

  • Repeat this process 5 times—required particularly after clearing codes

2. Drive sufficient miles under varied conditions

  • CARB recommends normal business use for several days, covering varied driving conditions.

  • Aim for 50–100 miles total, including highway segments, to allow all OBD monitors (catalyst, evaporative systems, oxygen sensors) to complete ww2.arb.ca.gov.

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3. Run a proper drive cycle

A drive cycle ensures the onboard systems test all monitors:

  • Start from a cold engine (< 122°F/50°C)

  • Idle in “Drive” (with A/C/defroster on) for 2–3 minutes

  • Turn off accessories and accelerate steadily to ~55 mph (88 km/h) and hold for ~3 minutes

  • Incorporate highway and stop‑and‑go driving to cover all monitors .

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4. Wait and retest if still “Not Ready”

  • If the OBD test returns “Not Ready,” continue regular use for a few more days and retest 

5. Resolve any remaining fault triggers

  • Some components may fail to set readiness flags until underlying issues (e.g. faulty sensors, EVAP leaks) are fixed. Repair these before retrying.

💡 Summary

To restore OBD readiness after code clears or repairs:

No DTCs/Permanent DTCs (PDTCs) shall be present, and vehicles must have:

  • at least five (5) WUC SCC, or

  • at least 200 miles travelled SCC, or

  • at least 400 minutes engine run time SCC, or

  • at most two (2) incomplete OBD Monitors.

If a PDTC is present, the Code will be ignored if the vehicle has:

  • at least 15 WUC SCC, or

  • at least 400 miles travelled SCC, or

  • at least 800 minutes engine run time SCC, or

  • at most one (1) incomplete OBD Monitor.​

 

An OBD test submitted to the Clean Truck Check that does not meet the above criteria will get a Not Ready test result and will not meet the emissions compliance testing requirements. If your vehicle receives a “Not Ready” OBD test result, you COULD continue operating the vehicle under normal business practices for a few days and then have the vehicle retested.

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