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As stated in the subject header, How does VTM work exactly? I have a 2004 Pilot EX with Navi and I am fascinated about what VTM does and how it contributes to the pilot being a great light-off-roading vehicle. Also I am not too sure how the 4WD works.

From my understanding, pilot primarily front wheel drive until it detects slippage on the front tires. When it detects slippage on the front tires, the transmission then diverts torque to the rear tires.

Please, clarify how VTM operates in relation to the 4WD system of a 2004 Pilot.
 

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Alpo714 said:

How does VTM work exactly?

VTM-4 Engagement Modes

There are three distinct modes of VTM-4 engagement:

(1) The first mode, called Acceleration Torque Control (ATC), works whenever the vehicle's throttle is depressed, even on dry pavement - a feature unique to the VTM-4 system. Sensors in the engine and transmission monitor vehicle speed and acceleration. The amount of torque applied, as directed by the system's ECU, is determined according to vehicle speed, the amount of acceleration and transmission status (gear setting). This benefits not only the Pilot's ability to gain traction from a standing start, before wheel slip occurs, but also its overall dynamic stability on both dry and slippery roads. Reducing the propulsive force carried by the front tires under acceleration reduced torque steer and cornering adhesion. Rear wheel torque rises smoothly from zero to a preset maximum in proportion to vehicle acceleration (both forward and reverse). During constant-speed driving, all power is driven to the front wheels for improved fuel efficiency.

(2) The second engagement mode occurs when wheel slip is detected. Differences in rotational speed between front and rear wheels are measured by sensors in the ABS system and monitored by the ECU. In response, the ECU commands an increase in torque delivery to the rear wheels. Torque application is adjusted according to the amount and the rate of change in wheel slip. As slip increase, more power is delivered to the rear wheels for improved traction.

(3) The third mode of engagement is VTM-4 Lock. Lock mode occurs when the driver shifts into first, second or reverse gears and depresses the VTM-Lock button on the instrument panel. When lock mode is selected at vehicle speeds below 18-mph, the system ECU commands a preset maximum amount of rear-drive torque to be delivered to the rear wheels for improved traction in very low-speed, low-traction, conditions. As control is regained and vehicle speed increases, the system gradually reduces rear axle torque until it is completely disengaged.
 

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Discussion Starter #4
Re: Re: How Does VTM Work?

xGS said:


VTM-4 Engagement Modes

There are three distinct modes of VTM-4 engagement:

(1) The first mode, called Acceleration Torque Control (ATC), works whenever the vehicle's throttle is depressed, even on dry pavement - a feature unique to the VTM-4 system. Sensors in the engine and transmission monitor vehicle speed and acceleration. The amount of torque applied, as directed by the system's ECU, is determined according to vehicle speed, the amount of acceleration and transmission status (gear setting). This benefits not only the Pilot's ability to gain traction from a standing start, before wheel slip occurs, but also its overall dynamic stability on both dry and slippery roads. Reducing the propulsive force carried by the front tires under acceleration reduced torque steer and cornering adhesion. Rear wheel torque rises smoothly from zero to a preset maximum in proportion to vehicle acceleration (both forward and reverse). During constant-speed driving, all power is driven to the front wheels for improved fuel efficiency.

(2) The second engagement mode occurs when wheel slip is detected. Differences in rotational speed between front and rear wheels are measured by sensors in the ABS system and monitored by the ECU. In response, the ECU commands an increase in torque delivery to the rear wheels. Torque application is adjusted according to the amount and the rate of change in wheel slip. As slip increase, more power is delivered to the rear wheels for improved traction.

(3) The third mode of engagement is VTM-4 Lock. Lock mode occurs when the driver shifts into first, second or reverse gears and depresses the VTM-Lock button on the instrument panel. When lock mode is selected at vehicle speeds below 18-mph, the system ECU commands a preset maximum amount of rear-drive torque to be delivered to the rear wheels for improved traction in very low-speed, low-traction, conditions. As control is regained and vehicle speed increases, the system gradually reduces rear axle torque until it is completely disengaged.
Wow. That is an incredibly detailed response. Thanks xGS!
 

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Question

In the second engagement mode, I have noticed a slight, momentary drag. Is the ABS engaging to help correct the slippage?

I ask because during some recent storms in the Northeast, on a slippery hill, I can feel one or more wheels slipping, then a mometary drag, like someone is touching the brakes and then the vehicle surges with what feels like four wheel drive. It then powers forward, starts to slip, slight drag and the takes off again. This will continue if I'm too aggressive for the driving conditions.


And by the way, I have new Michellin M+S tires.
 

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mriley said:
In the second engagement mode, I have noticed a slight, momentary drag. Is the ABS engaging to help correct the slippage?
i believe that's the VSA (traction control) kicking in. i've experienced the same drag or hesitation upon hard acceleration on icy/wet pavement, accompanied by the flashing VSA symbol in the instrument cluster.
 

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Re: Re: How Does VTM Work?

xGS said:


VTM-4 Engagement Modes

There are three distinct modes of VTM-4 engagement:

(1) The first mode, called Acceleration Torque Control (ATC), works whenever the vehicle's throttle is depressed, even on dry pavement - a feature unique to the VTM-4 system. Sensors in the engine and transmission monitor vehicle speed and acceleration. The amount of torque applied, as directed by the system's ECU, is determined according to vehicle speed, the amount of acceleration and transmission status (gear setting). This benefits not only the Pilot's ability to gain traction from a standing start, before wheel slip occurs, but also its overall dynamic stability on both dry and slippery roads. Reducing the propulsive force carried by the front tires under acceleration reduced torque steer and cornering adhesion. Rear wheel torque rises smoothly from zero to a preset maximum in proportion to vehicle acceleration (both forward and reverse). During constant-speed driving, all power is driven to the front wheels for improved fuel efficiency.

(2) The second engagement mode occurs when wheel slip is detected. Differences in rotational speed between front and rear wheels are measured by sensors in the ABS system and monitored by the ECU. In response, the ECU commands an increase in torque delivery to the rear wheels. Torque application is adjusted according to the amount and the rate of change in wheel slip. As slip increase, more power is delivered to the rear wheels for improved traction.

(3) The third mode of engagement is VTM-4 Lock. Lock mode occurs when the driver shifts into first, second or reverse gears and depresses the VTM-Lock button on the instrument panel. When lock mode is selected at vehicle speeds below 18-mph, the system ECU commands a preset maximum amount of rear-drive torque to be delivered to the rear wheels for improved traction in very low-speed, low-traction, conditions. As control is regained and vehicle speed increases, the system gradually reduces rear axle torque until it is completely disengaged.

What does ECU stand for?
 

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i have a 2004 honda pilot, not sure the trim level
it has the vtm 4 lock button
does this mean it has the 4wd auto aspect?
can a pilot be a fwd with a vtm 4lock only? meaning it isnt 4wd beyond low gear/get unstuck mode?
 

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i have a 2004 honda pilot, not sure the trim level
it has the vtm 4 lock button
does this mean it has the 4wd auto aspect?
can a pilot be a fwd with a vtm 4lock only? meaning it isnt 4wd beyond low gear/get unstuck mode?
Your 2004 is front wheel drive and the VTM-4 automatically activates when needed. You can also manually activate VTM-4 mode as well. XGS in one of the posts above has a great explanation of how it works.
 

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So it is 4wd that activates as needed, just in my experience it’s hard to tell or know it’s activated, I do a lot of winter and snow driving
 

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So it is 4wd that activates as needed, just in my experience it’s hard to tell or know it’s activated, I do a lot of winter and snow driving
The Pilot's AWD/VTM-4 system was originally introduced on the MDX and was designed, as Honda then described it, to "defeat winter" - as opposed to climb rocks.
However, the performance of the system will only be as good as the grip of your tires allows it to be.
What tires are you using?
 

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VTM-4 Engagement Modes

There are three distinct modes of VTM-4 engagement:

(1) The first mode, called Acceleration Torque Control (ATC), works whenever the vehicle's throttle is depressed, even on dry pavement - a feature unique to the VTM-4 system. Sensors in the engine and transmission monitor vehicle speed and acceleration. The amount of torque applied, as directed by the system's ECU, is determined according to vehicle speed, the amount of acceleration and transmission status (gear setting). This benefits not only the Pilot's ability to gain traction from a standing start, before wheel slip occurs, but also its overall dynamic stability on both dry and slippery roads. Reducing the propulsive force carried by the front tires under acceleration reduced torque steer and cornering adhesion. Rear wheel torque rises smoothly from zero to a preset maximum in proportion to vehicle acceleration (both forward and reverse). During constant-speed driving, all power is driven to the front wheels for improved fuel efficiency.

(2) The second engagement mode occurs when wheel slip is detected. Differences in rotational speed between front and rear wheels are measured by sensors in the ABS system and monitored by the ECU. In response, the ECU commands an increase in torque delivery to the rear wheels. Torque application is adjusted according to the amount and the rate of change in wheel slip. As slip increase, more power is delivered to the rear wheels for improved traction.

(3) The third mode of engagement is VTM-4 Lock. Lock mode occurs when the driver shifts into first, second or reverse gears and depresses the VTM-Lock button on the instrument panel. When lock mode is selected at vehicle speeds below 18-mph, the system ECU commands a preset maximum amount of rear-drive torque to be delivered to the rear wheels for improved traction in very low-speed, low-traction, conditions. As control is regained and vehicle speed increases, the system gradually reduces rear axle torque until it is completely disengaged.

Perfectly explained here. I would only add that for situation #3, disabling VSA (by pressing its button) improves traction even more, if you're really stuck.
 
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