We understand having replaced the battery on your Nissan 370z caused it's Emission Monitors to erase; requiring you drive the vehicle through a drive cycle. Let's briefly explain what emission monitors are. Emission monitors are internal self-tests which the power control module (PCM) performs in order to ensure a vehicle's emission systems, such as the EGR, EVAP, oxygen sensor, O2 heater, and catalyst (catalytic converter) are functioning properly. If any one monitor is incomplete (excluding the EVAP monitor; at the time of this post), your Nissan 370z will not be able pass the smog test. The EVAP monitor is the only monitor allowed to remain incomplete and the vehicle still pass the smog check because of the difficulty of getting this particular monitor to complete. In order to get the monitors ready for the smog check you'll need to drive your car through a Nissan 370z drive cycle.
Usually 200-300 miles of driving, and over the course of a few days and in both city and highway traffic conditions, is enough to get the drive cycle complete. Due to individual vehicle owner driving patterns however, sometimes the criteria required to get a particular monitor to initiate and/or become ready is not met. In such instances, it is required that a specific drive cycle pattern which is designed for the Nissan 370z be followed.
How to Complete a Nissan 370z Drive Cycle
Performing the driving pattern below will allow your Nissan to make ready all I/M emission monitors in preparation for a smog inspection. Follow the drive cycle carefully. Take extra caution when performing the drive cycle on public roadways. If you feel you will be unable to follow the Nissan drive cycle safely, please seek assistance from an smog check repair station or Nissan dealership. They may be able to perform the drive cycle utilizing a dynamometer, and specialized scan tools; instead of driving the vehicle. Perform the drive cycle at your own risk.
It is best to start the driving cycle in the morning; after a cold soak. A "cold soak" is the act of allowing an engine to cool down overnight. The definition of a cold soak, in engine mechanic terms, is to give the vehicle time to sit at low temperatures, typically below 68°F, or until the internal and external components of the vehicle's engine have had enough time to thoroughly cool down; allowing the PCM to reset the EVAP monitor timer.
Ensure the Check Engine Light is not on.
Gas tank fuel level must be between 15% and 85% during the drive cycle.
Engine temperature requirement is between 68 and 86 degrees F prior to drive cycle start.
START HERE - The Drive Trace:
A. Start your Nissan 370z and idle engine until coolant temperature reaches 160F (until normal operating temperature is reached).
B. With the engine warm and using a timer (for precision), idle the engine for an additional 1 1/2 minutes.
C. Begin driving. Accelerate smoothly to 56 mph with the transmission in Drive (standard power mode and transmission in auto mode) then release gas pedal and coast for 10 seconds.
D. Accelerate again 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 370z 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. It is more important to maintain accelerator pedal position than speed in this step. You are allowed a 3 mph variance in speed, but must try and keep the accelerator pedal steady.
- End of Drive Cycle -
Assuming your vehicle's emission systems are functioning properly, completing the drive cycle above should allow the required emission monitors (readiness flags) to become READY / COMPLETE for the smog inspection. If you have access to an OBDII scan tool (generic scan tool will do fine) you can check the readiness status of the various monitors before visiting a smog check station again. If you do not have a scan tool or prefer not to purchase one, consider asking a local auto parts store to run a quick status check. They usually offer this service for free in anticipation that you'll purchase any required replacement parts from them. Note this free service may or may not be allowed in your State.