Sounds like your Toyota Tundra has had its emission monitors (also known as readiness flags) erased at some point while it was being worked on, either due to the battery being disconnected or trouble codes being cleared (which subsequently also erases Emission Monitors).
Driving your Toyota Tundra in order to make READY the emission monitors is correct, however a specific driving pattern, known as a Drive Cycle, must be followed in order to make the monitors ready, and allow your truck to pass the smog inspection.
The following Drive Cycle should set all the required emission monitors. Follow them carefully and as accurately as possible. Take extra caution when performing the drive cycle on public roadways. If you feel you will not be able to complete the driving pattern safely please seek assistance from a Toyota dealership. The dealer will be able to perform the drive cycle on a dynamometer, eliminating the need to drive the truck on streets and freeways.
Begin by: (It is very important to make sure your Toyota Tundra has only between 1/4 and 3/4 of fuel in the gas tank. Some of the monitors (particularly the EVAP monitor) will not run while your truck has any amount of fuel other than 1/4 to 3/4 tank.
- Start the engine. Idle the engine in drive for two and a half minutes with the A/C and rear defroster on.
- Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle.
- Hold at a steady speed of 55 mph for three minutes.
- Decelerate (coast down) to 20 mph without braking.
- Accelerate back to 55 to 60 mph at ¾ throttle.
- Hold at a steady speed of 55 to 60 mph for five minutes.
- Decelerate (coast down) to a stop without braking.
If all other emissions systems are functioning properly, completing the drive cycle above should set the emission monitors required to pass the smog test. We recommend performing the drive cycle 2 or 3 times before the smog inspection. Using a scan tool check which monitors have become ready after each drive cycle.
