top of page

How to Complete a Drive Cycle Before Your Smog Check

Last updated: October 22, 2026

A drive cycle is a set of driving steps that lets your car's computer rerun its emissions self tests, called readiness monitors. You may need one after a battery change, a code clear, or repairs. Plan on 4 structured rounds, or about 2 weeks and 200 miles of normal driving.

If your car's required readiness monitors show "not ready," it can't pass a smog check yet. Here at Joe's Drive Thru Smog Check™ Star Station in North Hollywood, we put together this simple guide to help you get your car ready the safe and legal way.

What is a drive cycle?

A drive cycle is a set of driving steps (a cold start, a short warm up, highway driving, city driving, then a rest with the engine off) that lets your car's computer rerun its emissions self tests, called readiness monitors. It's also called a warm up cycle. Do it only on safe, legal public roads, and follow your owner's manual.

According to the Bureau of Automotive Repair (BAR), most vehicles complete their readiness monitors during normal driving, but some need specific conditions such as speed, temperature, and engine load before a monitor will run.

When do you need a drive cycle?

You need a drive cycle after repairs, after codes are cleared, or after a dead, disconnected, or replaced battery. Any of these makes your car's computer forget its readiness monitors, and they show not ready until the car is driven enough for its self tests to run again. Idling alone won't do it.

The Bureau of Automotive Repair confirms that readiness monitors must be rerun after a repair like disconnecting the battery or replacing a defective emissions part.

How many monitors can be not ready to pass a California smog check?

Under the Bureau of Automotive Repair's current rules, a 2000 or newer gasoline vehicle can pass with only the evaporative (EVAP) monitor incomplete. A 1996 to 1999 gasoline vehicle can have any one monitor incomplete. Any other required monitor that still shows not ready means the car can't pass yet.

Incomplete monitors allowed to pass, by model year and fuel type:

  • 1996 to 1999, Gasoline: Any one

  • 2000 and newer, Gasoline: Evaporative system (EVAP) only

Source: BAR On Board Diagnostic Test Reference. BAR's "gas" group includes gasoline, propane, and natural gas, and the misfire, fuel, and comprehensive component monitors are ignored on these vehicles. These standards have been in place since May 4, 2015.

BAR adopted new regulations, effective October 1, 2025, that require all readiness monitors to be set. BAR says the current pass and fail criteria shown above stay unchanged while it phases the change in gradually, and that any change will be announced well in advance (BAR, Fall 2025).

Safety first

Please read this before you drive.

  • Do this only on safe, legal public roads.

  • Obey all speed limits, signs, and signals at all times.

  • No phone. Keep both hands on the wheel.

  • Drive in daylight and good weather, on lightly traveled roads.

  • If possible, bring a passenger to read the steps to you.

  • Your car must be in good mechanical condition.

  • If your check engine light is blinking, stop and see a repair shop.

Before you start

  1. Fill the tank to about three quarters full, not all the way.

  2. Park with the engine off for at least 6 hours. Overnight is easiest.

  3. Make sure the outside temperature is between 60 and 95 degrees F.

How to do a drive cycle, step by step

Follow your owner's manual if it lists a drive cycle for your car, and obey all traffic laws.

Step 1: Cold start and idle

Start the engine without touching the gas pedal, and let it idle for 20 seconds.

Step 2: Warm up

In Park or Neutral, hold the engine at about 2,000 rpm for about 3 minutes, until the temperature gauge reaches about a quarter. Then let it idle for 20 seconds with your foot off the gas.

Step 3: Highway portion

Drive 55 to 60 mph for 20 or more minutes (use D or 5th gear), never above the posted speed limit.

  • Turn cruise control off.

  • When safe on a lightly traveled road, coast (lift off the gas, no brake) for a total of 90 seconds. This can be three 30 second coasts.

Step 4: City portion

Following city driving rules, drive in city or suburban traffic for 10 or more minutes.

  • Stop and go normally, and obey all signals and speed limits.

  • When safe, coast several seconds at a time (lift off the gas, no brake) to help the monitors complete.

Step 5: Park and rest 30 minutes

Park and turn the engine off for 30 minutes.

How long does a drive cycle take, and how many times do I repeat it?

Each round has a short warm up, 20 or more minutes of highway driving, 10 or more minutes of city driving, and 30 minutes parked with the engine off. Repeat the full process, steps 1 through 5, a total of 4 times, each from a cold start. Or simply drive normally for about 2 weeks and 200 miles.

The easier option: about 2 weeks and 200 miles of normal driving

Drive normally for about 2 weeks, putting on about 200 miles of mixed city and highway driving. That fits the Bureau of Automotive Repair's advice: "If you recently disconnected or replaced your battery, drive your vehicle for a week or two."

2010 and newer cars with a permanent code (PDTC)

For 2010 and newer vehicles, and permanent codes, put on more than 200 miles total and complete at least 16 warm up drive cycles.

BAR's limit is 15 warm up cycles and 200 miles. We suggest at least 16 warm ups and more than 200 miles for a margin. Here's how BAR's rule works: a 2010 or newer car with a permanent trouble code fails the smog check, but BAR ignores the code once the car has completed at least 15 warm up cycles and been driven at least 200 miles since its codes were last cleared (BAR On Board Diagnostic Test Reference). A permanent code can't be erased with a scan tool or by disconnecting the battery.

BAR defines a warm up cycle as driving so the engine coolant temperature rises at least 40 degrees F after the engine is started and reaches at least 160 degrees F (BAR, Permanent Diagnostic Trouble Codes).

How do I check if my monitors are ready?

Use an OBDII scanner. Its live data feed shows the number of warm ups since codes were cleared and the distance traveled since codes were cleared, so you can track your progress. Also make sure the check engine light is off, because BAR says a car won't pass a smog check with it on.

A drive cycle is also called a warm up cycle, so the warm up count on your scanner tells you how many you've completed. Use it to check your progress toward the 16 warm ups and more than 200 miles.

What if my monitors still aren't ready?

See a repair shop or dealer to have the monitor system checked. BAR notes that a vehicle may never complete a monitor until the parts that let it run are properly diagnosed and repaired. If you still have trouble after that, the state's Smog Check Referee can help at asktheref.org or (800) 622-7733.

Learn more: what a Not Ready or check engine result means, what each readiness monitor checks, and why a dead battery erases monitor data.

Drive cycle FAQ

What is a drive cycle?

A drive cycle is a set of driving steps (a cold start, a warm up, highway driving, city driving, then a rest with the engine off) that lets your car's computer rerun its emissions self tests, called readiness monitors. It's also called a warm up cycle. Do it only on safe, legal public roads, and follow your owner's manual.

Why do my monitors show not ready after a battery change or code clear?

Disconnecting or replacing the battery, clearing codes, or emissions repairs reset the readiness monitors. California's Bureau of Automotive Repair says the monitors must be rerun after a battery disconnect or emissions repair. They only finish when the car is driven enough for its self tests to run again, so idling won't do it.

How long does a drive cycle take?

Each round includes a short warm up, 20 or more minutes of highway driving, 10 or more minutes of city driving, then 30 minutes parked. Repeat it a total of 4 times, each from a cold start. Or drive normally for about 2 weeks and 200 miles, which fits BAR's advice to drive for a week or two.

How many monitors can be not ready to pass a smog check in California?

Under BAR's current rules, a 2000 or newer gasoline vehicle can pass with only the evaporative (EVAP) monitor incomplete, and a 1996 to 1999 gasoline vehicle can have any one monitor incomplete. A rule effective October 1, 2025 requires all monitors to be set, but BAR says these criteria stay in place while it phases the change in.

My 2010 or newer car has a permanent code. How much do I need to drive?

BAR fails 2010 and newer cars with a permanent code, but ignores it after at least 15 warm up cycles and 200 miles since the last code clear. We suggest at least 16 warm ups and more than 200 miles for a margin. A warm up cycle means the coolant rises at least 40 degrees F and reaches at least 160 degrees F.

What should I do before coming in for my smog check?

Finish the drive cycle or about 2 weeks of normal driving, and avoid disconnecting the battery or clearing codes again, since that resets the monitors. If you have an OBDII scanner, check your progress, and make sure the check engine light is off. Then drive up to Joe's Drive Thru Smog Check™, no appointment needed.

Can I complete a drive cycle without driving, just by idling?

No. Idling alone won't set the monitors. They need specific conditions, such as speed, temperature, and engine load, that come from real driving. BAR notes that some manufacturer drive cycles can't be done in traffic and need dynamometer equipment, so if yours won't set after normal driving, have a repair shop check it.

What if my monitors still aren't ready after the drive cycle?

Have a repair shop or dealer check the monitor system. BAR notes that some monitors will never complete until the parts that let them run are properly diagnosed and repaired. If you still have trouble meeting the readiness requirements, the state's Smog Check Referee can help at asktheref.org or (800) 622-7733.

Ready for your smog check?

Once your monitors are ready, come see us at Joe's Drive Thru Smog Check™ Star Station, 10909 Burbank Blvd, North Hollywood, CA 91601, (818) 760-0703 (get directions).

  • Walk in drive thru, no appointment needed (how our drive thru works).

  • Most checks take about 10 minutes, and you stay in your car the whole time.

  • $60 total out the door, including the $8.25 state smog certificate fee.

  • Hours: Monday to Friday 9:00 AM to 6:00 PM, Saturday 9:00 AM to 2:00 PM, Sunday closed.

  • We test 2000 to 2026 gasoline and hybrid light duty vehicles up to 7 feet tall. No diesel.

  • With our PASS OR DON'T PAY® policy, you only pay if your car passes.

Have more questions? Visit our smog check FAQ.

Liability notice: This guide is for educational purposes only, and you follow it at your own risk. JOE'S DRIVE THRU SMOG CHECK™ is not responsible for any damage, accidents, tickets, or failed tests. Check your owner's manual, and ask a certified technician if you're unsure.

bottom of page