It’s a common concern for Chevrolet Silverado owners: Active Fuel Management (AFM) and its impact on engine performance and fuel efficiency. Many seek ways to disable AFM, and OBDII scan tools are often considered as a potential solution. This article delves into whether OBDII scan tools can turn off Active Fuel Management on a Silverado, drawing insights from real-world experiences and expert knowledge.
Recently, a Silverado owner shared their experience with an AFM disabler and a state emissions test, highlighting a crucial point for anyone using these devices. The owner of a 2015 Silverado 2wd 4.3L V6, after using a Range AFM disabler, encountered an issue when taking their truck for a Missouri state emission test. Prior to the test, the disabler was removed. The test, which involved plugging into the OBDII port to read emission sensors, resulted in a failure. The O2 sensor and catalytic converter were flagged as “not completed” in the readiness system test.
The mechanic inquired about recent battery replacements or code clearing, suspecting a reset of the emissions system. However, neither had occurred. This led the truck owner to question if removing the AFM disabler could be the cause. Contacting Range Technology, the manufacturer of the disabler, confirmed this suspicion.
Range Technology’s support team stated, “As of right now, the AFM disablers are not emissions approved and can cause the vehicle to fail.” They further explained, “Disabling and then re-enabling the AFM system does reset the vehicle’s emissions readiness systems. We do recommend driving the vehicle for 50-100 total miles with the device removed to allow the emissions systems to fully reset before going to get the vehicle tested.“
This experience underscores a vital point: AFM disablers can indeed affect your vehicle’s emissions readiness. But where do OBDII scan tools fit into this picture, and can they directly turn off AFM?
While OBDII scan tools are powerful diagnostic tools capable of reading and clearing trouble codes, monitoring sensor data, and performing various system tests, their primary function is not to permanently alter engine management systems like AFM. Standard OBDII scan tools are designed for diagnostics and maintenance, not for re-programming core engine functions like AFM on/off control.
Think of OBDII scan tools as interpreters and troubleshooters of your vehicle’s onboard computer. They can read the language of your engine control unit (ECU) and identify problems, but they generally cannot rewrite the fundamental software that dictates how systems like AFM operate.
Specialized tuning tools or programmers, which go beyond basic OBDII functionality, are often required to make permanent changes to AFM settings. These tools are typically used by experienced tuners and are not standard OBDII scan tools that you would use for regular diagnostics or emissions checks.
Therefore, while an OBDII scan tool can help you read emissions readiness status and potentially clear codes related to emissions issues (after addressing the root cause), it cannot directly “turn off” Active Fuel Management in your Silverado. The experience shared by the Silverado owner highlights that devices designed to disable AFM can interfere with emissions readiness monitors, and a proper drive cycle is needed after removing such devices to ensure your vehicle is ready for an emissions test.
Key Takeaways:
- OBDII scan tools are diagnostic tools: They are not designed to permanently disable systems like AFM.
- AFM disablers affect emissions readiness: Removing an AFM disabler can reset emissions monitors, leading to test failures if not properly addressed.
- Drive cycle is crucial: After removing an AFM disabler, drive your Silverado for 50-100 miles to allow emissions systems to reset before an emissions test.
- Specialized tools for AFM modification: Turning off AFM permanently usually requires specialized tuning equipment, not standard OBDII scan tools.
Understanding the limitations of OBDII scan tools and the impact of AFM disablers on emissions is essential for Silverado owners. For emissions testing, ensure any AFM disablers are removed and your vehicle has completed a proper drive cycle to avoid unexpected failures.
