Tow haul mode is a feature found on many trucks and SUVs designed to optimize performance when pulling heavy loads. While it can be a valuable tool for towing, many drivers wonder if using it when not towing can cause harm or offer any benefits. Understanding the function of tow haul mode and its potential effects on your vehicle is crucial for making informed decisions about its use. This article will delve into the specifics of tow haul mode, its impact on various vehicle components, and whether or not it's advisable to use it when unladen.
| Feature | Effect of Tow Haul Mode | Explanation |
|---|---|---|
| Shift Points | Higher RPMs | Tow haul mode typically raises the engine RPMs at which the transmission shifts. This keeps the engine in its power band for longer, providing more torque for towing. |
| Throttle Response | Increased Sensitivity | The throttle becomes more responsive, providing quicker acceleration and improved control when towing a heavy load. |
| Transmission Cooling | Enhanced | Some vehicles with tow haul mode activate additional transmission cooling features to prevent overheating while towing. |
| Engine Braking | Increased | Tow haul mode often increases engine braking, especially on downhill grades. This helps to control the vehicle's speed and reduces wear on the brakes. |
| Fuel Economy | Decreased | Due to the higher RPMs and more aggressive throttle response, fuel economy generally decreases when using tow haul mode. |
| Transmission Wear | Potentially Increased | While designed to protect the transmission under heavy load, using tow haul mode unnecessarily can potentially increase wear due to the higher operating pressures and temperatures. |
| Ride Comfort | Potentially Reduced | The more aggressive shifting and increased engine braking can result in a less smooth and comfortable ride. |
| Emissions | Potentially Increased | Higher RPMs and a richer fuel mixture (in some cases) can lead to increased emissions. |
| Overall Vehicle Life | Potentially Reduced | While not directly detrimental in the short term, prolonged and unnecessary use of tow haul mode could contribute to accelerated wear and tear on various components over the lifespan of the vehicle. |
| Torque Converter Lockup | Earlier Lockup | Tow haul mode often commands the torque converter to lock up earlier and more frequently. This improves efficiency and reduces heat build-up when towing. |
| ABS/Stability Control | Modified | In some vehicles, tow haul mode may adjust the parameters of the ABS and stability control systems to account for the increased weight and handling characteristics of a towed load. |
| Differential Gear Ratio | No Direct Change | Tow haul mode does not change the differential gear ratio. The differential gear ratio is a fixed mechanical component. |
| Engine Temperature | Potentially Increased | While extra cooling may be activated, the increased engine workload from higher RPMs can potentially lead to slightly higher engine temperatures. |
| Diagnostic Trouble Codes | No Direct Trigger | Using tow haul mode when not towing should not directly trigger any diagnostic trouble codes (DTCs). However, excessive strain on components could eventually lead to DTCs over a long period. |
Detailed Explanations
Shift Points: Tow haul mode alters the transmission's shift points, causing it to hold gears longer and shift at higher RPMs. This allows the engine to operate in its peak power range, which is essential for pulling heavy loads. When not towing, these higher shift points can result in a less efficient and potentially more stressful operation for the engine.
Throttle Response: Tow haul mode typically increases the sensitivity of the throttle. This means that a smaller movement of the accelerator pedal results in a larger change in engine output. While beneficial for precise control when towing, this heightened sensitivity can make the vehicle feel jumpy and less comfortable to drive in normal conditions.
Transmission Cooling: Some vehicles equipped with tow haul mode also incorporate enhanced transmission cooling systems. These systems may include larger transmission coolers or other features designed to prevent overheating during heavy towing. While this extra cooling is beneficial when towing, it has minimal impact when not towing, although it won't cause harm.
Engine Braking: Engine braking is the process of using the engine's resistance to slow the vehicle down. Tow haul mode often increases engine braking, especially on downhill grades. This is particularly useful when towing heavy loads, as it helps to control the vehicle's speed and reduces the reliance on the brakes. When not towing, the increased engine braking can feel jerky and less smooth.
Fuel Economy: Due to the higher RPMs and more aggressive throttle response associated with tow haul mode, fuel economy generally decreases when using it. The engine is working harder and consuming more fuel to maintain the higher RPMs, even when not under load.
Transmission Wear: While tow haul mode is designed to protect the transmission under heavy load, using it unnecessarily can potentially increase wear. The higher operating pressures and temperatures associated with the higher RPMs and more aggressive shifting can put extra strain on the transmission components over time.
Ride Comfort: The more aggressive shifting and increased engine braking associated with tow haul mode can result in a less smooth and comfortable ride. The vehicle may feel jerky and less responsive to subtle changes in throttle input.
Emissions: Higher RPMs and a richer fuel mixture (in some cases) can lead to increased emissions. The engine is working harder and consuming more fuel, resulting in a higher output of pollutants.
Overall Vehicle Life: While not directly detrimental in the short term, prolonged and unnecessary use of tow haul mode could contribute to accelerated wear and tear on various components over the lifespan of the vehicle. The increased stress on the engine, transmission, and other drivetrain components can potentially shorten their lifespan.
Torque Converter Lockup: The torque converter acts as a fluid coupling between the engine and transmission. Tow haul mode often commands the torque converter to lock up earlier and more frequently. This eliminates slippage and improves efficiency, especially when towing. When not towing, this earlier lockup can make the shifts feel harsher.
ABS/Stability Control: In some vehicles, tow haul mode may adjust the parameters of the ABS (Anti-lock Braking System) and stability control systems to account for the increased weight and handling characteristics of a towed load. These adjustments may not be optimal for normal driving conditions without a trailer.
Differential Gear Ratio: Tow haul mode does not change the differential gear ratio. The differential gear ratio is a fixed mechanical component that determines the relationship between the engine's RPM and the wheels' RPM. Tow haul mode only affects the transmission's shift points and other electronic controls.
Engine Temperature: While extra cooling may be activated, the increased engine workload from higher RPMs can potentially lead to slightly higher engine temperatures, especially on longer drives. This is generally not a significant concern for modern engines, but it's still a factor to consider.
Diagnostic Trouble Codes: Using tow haul mode when not towing should not directly trigger any diagnostic trouble codes (DTCs). However, excessive strain on components over a long period could potentially lead to DTCs related to transmission or engine performance.
Frequently Asked Questions
Will using tow haul mode when not towing damage my transmission? While occasional use is unlikely to cause immediate damage, prolonged and unnecessary use can potentially increase wear and tear on the transmission over time.
Does tow haul mode improve fuel economy when not towing? No, tow haul mode almost always decreases fuel economy due to the higher RPMs and more aggressive throttle response.
Can I use tow haul mode for better acceleration when not towing? While it may provide slightly quicker acceleration, the increased wear and tear and decreased fuel economy outweigh the benefits for everyday driving.
Will tow haul mode make my truck ride rougher? Yes, the more aggressive shifting and increased engine braking can result in a less smooth and comfortable ride.
Is it okay to use tow haul mode on a steep hill when not towing? In some cases, using tow haul mode on a steep downhill grade without a load can provide enhanced engine braking, but it's generally not necessary and may result in a jerky ride.
Will tow haul mode increase my engine's temperature when not towing? Potentially, yes. The increased engine workload from higher RPMs can lead to slightly higher engine temperatures, especially on longer drives.
Does tow haul mode affect my vehicle's stability control system? Yes, in some vehicles, tow haul mode may adjust the parameters of the ABS and stability control systems.
Can using tow haul mode when not towing void my warranty? It is highly unlikely that using tow haul mode when not towing will void your warranty, as it is a built-in feature of the vehicle. However, excessive wear and tear caused by misuse could potentially lead to warranty claims being denied.
Does tow haul mode change my differential gear ratio? No, tow haul mode does not change the differential gear ratio. The differential gear ratio is a fixed mechanical component.
Will using tow haul mode when not towing cause any error codes? No, using tow haul mode when not towing should not directly trigger any diagnostic trouble codes (DTCs).
Conclusion
While tow haul mode is a valuable tool for optimizing vehicle performance when towing heavy loads, using it when not towing generally offers no benefits and can potentially lead to increased wear and tear, decreased fuel economy, and a less comfortable ride. It's best to reserve tow haul mode for its intended purpose: towing.