Are you experiencing a brief pause when you hit the gas in your GM pickup? Here’s what you need to know.
If you’re the proud owner of a General Motors vehicle, particularly a Chevrolet Silverado / Colorado or GMC Sierra / Canyon, you may have encountered a moment of hesitation when you accelerate. This isn’t just you; it’s a known characteristic of certain GM models, and there’s a technical explanation behind it.
What’s Happening Under the Hood?
General Motors has released an updated Technical Service Bulletin (23-NA-153) that covers this phenomenon. This hesitation, often perceived as a sag or delay in response when you aggressively apply the throttle, is particularly noticeable under two conditions:
Low-Speed Maneuvers: When you’re coasting at speeds below 15 mph with a closed throttle and then suddenly apply the throttle. This can occur during actions like a rolling stop or a lane change.
High-Speed Scenarios: When cruising at highway speeds and then quickly increasing the throttle, forcing a downshift.
The Role of Torque Management
The underlying cause of this hesitation is the vehicle’s torque management system. Here’s what happens:
In low-speed maneuvers, when the throttle is applied aggressively, the throttle blade opens slowly (up to 0.7 seconds). This delay is intentional to minimize driveline lash and prevent clunking.
In scenarios involving a hard stop followed by an aggressive throttle, especially in automatic transmissions, there’s a brief period (about 0.5 seconds) of “zero” torque command. This allows the transmission to complete its downshift to first gear.
Similarly, during high-speed driving, when a sudden increase in throttle forces a downshift, about 0.5 seconds of “zero” torque might be commanded to allow the downshift to complete.
What Does This Mean for GM Vehicle Owners?
It’s important to understand that these conditions are a normal part of the vehicle’s design, aimed at ensuring smoother and more controlled vehicle behavior. These are not flaws, but rather, features intended to enhance your driving experience and the vehicle’s longevity. GM advises that no repairs should be attempted for these conditions as they are considered normal operational characteristics.
What Should You Do?
As a GM vehicle owner, especially if you’re new to the world of trucks and automobiles, awareness is key. Understanding how your vehicle operates under various conditions can enhance your driving experience and your relationship with your vehicle.
For more detailed information and assistance, it’s always a good idea to consult with your local GM dealership or a qualified technician. Remember, staying informed and understanding your vehicle’s operational characteristics is a crucial part of the automotive experience.
For additional information, ask your dealer to reference TSB 23-NA-153