Having replaced your Nissan Altima's battery caused the OBDII monitors to clear themselves, requiring a drive cycle be completed in order to make the monitors READY or COMPLETE again. Follow the Nissan Altima drive cycle below. You shouldn't necessarily need to have the Nissan dealership perform the drive cycle electronically. The required monitors should become ready to pass the smog inspection simply by driving your Altima for 200-300 miles and over the course of a few days. We notice you mention having already driven thousands of miles. We'd like to note, due to individual driving habits/patterns, sometimes the drive cycle parameters are not met with ordinary driving, and following the Nissan Altima drive cycle is necessary.
Take extra caution when performing drive cycles on public roadways, obeying all traffic laws. You may also seek repair assistance from a Nissan dealership. They will be able to complete the drive cycle using manufacture specific scan tools. If after performing the drive cycle twice, your Altima is still unable to pass the smog check because its monitors (or monitor) is incomplete, please seek assistance from a smog check repair center or Nissan dealership.
How to Complete a Nissan Altima Drive Cycle
Pre-Conditioning Requirements:
Ensure the MIL (malfunction indicator lamp) is not on.
Gas tank fuel level must be between 15% and 85% at all times.
Drive cycle must start while engine is cold; best performed in the morning, after being parked overnight. The actual requirement is that the engine be between 68 and 86 degrees F prior to the start of the drive cycle.
Drive Trace:
A. Start your vehicle and idle engine until coolant temperature reaches 160F (until normal operating temperature is reached). Usually 20 minutes at idle will accomplish this.
B. Using a timer, idle the engine for an additional 1 1/2 minutes.
C. Begin driving. Accelerate smoothly to 56 mph with the transmission in (D) and overdrive ON, then release gas pedal and coast for 10 seconds.
D. Accelerate to 56 mph and maintain speed for at least 10 minutes. Use smooth and quick acceleration and maintain speed as constant as possible.
E. Stop and idle your Nissan Altima for 10 seconds.
F. Accelerate to 25 mph in 10 seconds and hold gas pedal steady for 20 seconds. Use smooth and quick acceleration and maintain speed as constant as possible.
G. Repeat steps E and F eight (8) times. Decelerate (coast down) to 15 mph and then drive for 13 minutes at speeds between 15mph and 35mph.
H. Accelerate to 53-56 mph and maintain speed for at least 6 minutes. In this step it is more important to maintain accelerator pedal position than speed. Therefore you are allowed 3 mph fluctuation in speed, but must try and keep the gas pedal steady.
- End of Drive Cycle -
If all emissions systems are functioning properly, completing the drive cycle above will set the emission monitors (also known as readiness flags) required to pass the smog check. If you have a generic scan tool you can check the monitor status before visiting a smog check station. A local auto parts store may be able to scan your Nissan's ECM and report monitor status as well. Auto part stores usually offer this service for free.
