Many Honda owners have noticed a peculiar feeling in their vehicles, especially models equipped with Variable Cylinder Management (VCM) systems. This sensation, often described as a slight shudder or hesitation, can be attributed to the VCM system engaging and disengaging cylinders for fuel efficiency. As a Honda owner myself, and a mechanic, I’ve explored ways to address this, and using an OBD2 scanner has been key to understanding and managing VCM.
In my previous Honda Pilot, the VCM system combined with a 6-speed automatic transmission often made the driving experience feel uncertain. It was hard to discern if the transmission was shifting gears or if VCM was activating. This led me to install an S-VCM device, which effectively disables the VCM system. The improvement was immediate – the car felt more responsive and the gear transitions became more predictable.
When I upgraded to a newer Pilot with a 9-speed automatic transmission, the VCM engagement seemed less intrusive. However, my curiosity led me to investigate further. Inspired by discussions on the Ridgeline forums about custom PID (Parameter IDs) for OBD2 scan tools, I decided to delve into monitoring the VCM system directly.
Using an OBD2 Bluetooth adapter and the Torque Pro app on my Android phone, I added custom PIDs to monitor both the current gear and the number of active cylinders in real-time. This setup allowed me to observe exactly when VCM was engaging and disengaging during driving. What I discovered was enlightening. Many instances I had previously interpreted as transmission downshifts were actually the VCM system switching between 3 and 6 cylinders. This was particularly noticeable when transitioning from coasting to accelerating uphill.
It’s also fascinating to see the 9-speed transmission in action. Cruising at around 38 mph, the transmission is already in 6th gear, highlighting its efficiency. My next step is to add engine temperature monitoring via the OBD2 scanner. Engine temperature is a crucial parameter for VCM activation, and I want to understand the temperature threshold at which VCM starts to operate.
Ultimately, my goal is to install the S-VCM device on my current Pilot as well. By using the OBD2 scanner both before and after installation, I can definitively verify that the S-VCM device effectively “spoofs” the engine temperature signal, preventing VCM from engaging and keeping all cylinders active at all times. This combination of VCM disable devices and OBD2 monitoring provides a comprehensive approach to understanding and optimizing the driving experience in Honda vehicles equipped with VCM.
