Active Fuel Management (AFM) systems in Chevrolet Silverados can be temporarily disabled using devices like Range Technology’s AFM disabler. However, it’s crucial to understand how this impacts emissions testing. Recently, a 2015 Silverado with a 4.3L V6 engine failed its emissions readiness test after the Range AFM disabler was removed. The vehicle had only been driven two miles after removing the device before the test. The failure was specifically related to the O2 sensor and catalytic converter, which showed a “not completed” status.
The manufacturer confirmed that AFM disablers are not emissions approved and can cause a vehicle to fail an OBDII emissions test. Disabling and re-enabling the AFM system resets the vehicle’s emissions readiness monitors. This means the vehicle’s computer needs time to run through its diagnostic cycles before the emissions system is considered ready.
Range Technology recommends driving 50-100 miles after removing the AFM disabler to allow the system to reset completely. This allows the O2 sensors and catalytic converter to reach their operational temperature and complete the necessary diagnostic checks. Only then should you proceed with an emissions test.
While OBDII scan tools can read and clear diagnostic trouble codes, they cannot directly turn off AFM. A scan tool can be used to monitor the status of the emissions readiness monitors after removing an AFM disabler. This can help determine if the vehicle is ready for testing. It’s important to consult your state’s specific emissions requirements and the manufacturer’s recommendations before modifying your vehicle’s emissions system. Using an unapproved AFM disabler could lead to failed emissions tests and potential fines.
Remember, ensuring your vehicle is emissions compliant is not only legally required but also contributes to environmental protection. Always follow the proper procedures when modifying your vehicle’s emissions systems. If you have questions regarding your vehicle’s emissions system and its readiness status, consult a qualified mechanic or contact the manufacturer for assistance.
