Just noticed today that the Jeep rolled back while sitting in traffic on a slight incline. Tried it on our steep driveway and it holds for about a second or two and then rolls back. Isn't it supposed to hold steady until you accelerate?
ferntree
Unless they changed it for 2014, it will only hold for a second or so. It's designed to hold from the time you lift your foot off the brake to you get it over to the go pedal. Not designed to hold indefinitely.
The HSA system is designed to assist the driver when
starting a vehicle from a stop on a hill. HSA will maintain
the level of brake pressure the driver applied for a short
period of time after the driver takes their foot off of the
brake pedal. If the driver does not apply the throttle
during this short period of time, the system will release
brake pressure and the vehicle will roll down the hill. The
system will release brake pressure in proportion to the
amount of throttle applied as the vehicle starts to move in
the intended direction of travel.
starting a vehicle from a stop on a hill. HSA will maintain
the level of brake pressure the driver applied for a short
period of time after the driver takes their foot off of the
brake pedal. If the driver does not apply the throttle
during this short period of time, the system will release
brake pressure and the vehicle will roll down the hill. The
system will release brake pressure in proportion to the
amount of throttle applied as the vehicle starts to move in
the intended direction of travel.
OK - thanks guys. Our Alfa back in Oz would just sit there on a hill until you hit the go pedal. I think the problem is there are almost no hills here on the Cape which is why I have never noticed the difference until today.
Appreciate the assistance - as usual!
Appreciate the assistance - as usual!
Probably more info than needed-
from the 2014 factory service manual:
Hill Start Assist (HSA)
The HSA system is designed to assist the driver when starting a vehicle from a stop on a hill. HSA will maintain the level of brake pressure the driver applied for a short period of time after the driver takes their foot off of the brake pedal. If the driver does not apply the throttle during this short period of time, the system will release brake pressure and the vehicle will roll down the hill. The system will release brake pressure in proportion to amount of throttle applied as the vehicle starts to move in the intended direction of travel. (this was already posted by 2kg4u)
WARNING!
If the clutch pedal (manual transmission only) remains pressed during the application of the throttle, the HSA will disengage allowing the vehicle to roll down the incline. This could cause a collision with another vehicle or object. To avoid this, do not apply throttle while pressing the clutch pedal until you are ready to release the clutch. Always remember the driver is responsible for braking the vehicle.
HSA Activation Criteria
The following criteria must be met in order for HSA to activate:
• Vehicle must be stopped
• Vehicle must be on an 8% (approximately) or greater incline (approximately 3% for manual transmission equipped vehicles)
• Gear selection matches vehicle uphill direction (i.e., vehicle facing uphill is in forward gear; vehicle backing uphill is in REVERSE gear).
WARNING!
There may be situations on minor hills with a loaded vehicle, or while pulling a trailer where the system will not activate and slight rolling may occur, which could cause a collision with another vehicle or object. Always remember the driver is responsible for braking the vehicle.
The system will only work if the intended direction of the vehicle and vehicle gear match. For example, if the intended direction is forward up a hill and the vehicle is in DRIVE (automatic transmission equipped vehicle), and the activation criteria are met, HSA will activate.
HSA On Automatic Transmission Vehicles
The system will work in REVERSE, and all forward gears on vehicles equipped with an automatic transmission. The system will not activate if the vehicle is placed in NEUTRAL.
HSA On Manual Transmission Vehicles
The system will work in REVERSE, forward gears, and NEUTRAL on manual transmission equipped vehicles. The system does not recognize NEUTRAL on manual vehicles, thus it will hold the vehicle on an incline for a short period while in NEUTRAL, regardless of clutch position. To prevent this, do not attempt to roll down a hill simply by putting the transmission in NEUTRAL and letting gravity act on the vehicle, as the HSA will prevent the vehicle from rolling. Instead, use the appropriate gear for moving in the desired direction.
Towing With HSA
HSA will provide assistance when starting on a grade when pulling a trailer.
WARNING!
• If you use a trailer brake controller with your trailer, your trailer brakes may be activated and deactivated with the brake switch. If so, when the brake pedal is released there may not be enough brake pressure to hold the vehicle and trailer on a hill and this could cause a collision with another vehicle or object behind you. In order to avoid rolling down the hill while resuming acceleration, manually activate the trailer brake prior to releasing the brake pedal. Always remember the driver is responsible for braking the vehicle.
• HSA is not a parking brake. Always apply the parking brake fully when leaving your vehicle. Also, be certain to leave the transmission in PARK.
• Failure to follow these warnings may cause the vehicle to roll down the incline and could collide with another vehicle, object or person, and cause serious or fatal injury. Always remember to use the parking brake while parking on a hill and that the driver is responsible for braking the vehicle.
NOTE: The HSA system may also be turned on and off if the vehicle is equipped with the Electronic Vehicle Information Center (EVIC). Refer to "Electronic Vehicle Information Center (EVIC)" in "Understanding Your Instrument Panel" for further information.
HSA Off
If you wish to turn off the HSA system, follow this procedure:
1. Start with the engine off and vehicle in PARK (automatic transmission) or NEUTRAL with clutch out (manual transmission) with wheels straight. Apply parking brake on manual transmission vehicle.
2. Start the engine.
3. With the engine running, the brake applied, and the clutch out, rotate the steering wheel 180° counterclockwise from center.
4. Press the ESC OFF switch four times within twenty seconds.
5. Rotate the steering wheel 360° clockwise (180° clockwise from center).
6. Cycle ignition switch OFF then ON.
7. If the sequence was completed properly, the "ESC Activation/Malfunction Indicator Light" will blink several times to confirm HSA is off.
Steps 1-7 must be completed within 90 seconds to turn off HSA. Repeat steps 1-7 to re-enable HSA functionality.
from the 2014 factory service manual:
Hill Start Assist (HSA)
The HSA system is designed to assist the driver when starting a vehicle from a stop on a hill. HSA will maintain the level of brake pressure the driver applied for a short period of time after the driver takes their foot off of the brake pedal. If the driver does not apply the throttle during this short period of time, the system will release brake pressure and the vehicle will roll down the hill. The system will release brake pressure in proportion to amount of throttle applied as the vehicle starts to move in the intended direction of travel. (this was already posted by 2kg4u)
WARNING!
If the clutch pedal (manual transmission only) remains pressed during the application of the throttle, the HSA will disengage allowing the vehicle to roll down the incline. This could cause a collision with another vehicle or object. To avoid this, do not apply throttle while pressing the clutch pedal until you are ready to release the clutch. Always remember the driver is responsible for braking the vehicle.
HSA Activation Criteria
The following criteria must be met in order for HSA to activate:
• Vehicle must be stopped
• Vehicle must be on an 8% (approximately) or greater incline (approximately 3% for manual transmission equipped vehicles)
• Gear selection matches vehicle uphill direction (i.e., vehicle facing uphill is in forward gear; vehicle backing uphill is in REVERSE gear).
WARNING!
There may be situations on minor hills with a loaded vehicle, or while pulling a trailer where the system will not activate and slight rolling may occur, which could cause a collision with another vehicle or object. Always remember the driver is responsible for braking the vehicle.
The system will only work if the intended direction of the vehicle and vehicle gear match. For example, if the intended direction is forward up a hill and the vehicle is in DRIVE (automatic transmission equipped vehicle), and the activation criteria are met, HSA will activate.
HSA On Automatic Transmission Vehicles
The system will work in REVERSE, and all forward gears on vehicles equipped with an automatic transmission. The system will not activate if the vehicle is placed in NEUTRAL.
HSA On Manual Transmission Vehicles
The system will work in REVERSE, forward gears, and NEUTRAL on manual transmission equipped vehicles. The system does not recognize NEUTRAL on manual vehicles, thus it will hold the vehicle on an incline for a short period while in NEUTRAL, regardless of clutch position. To prevent this, do not attempt to roll down a hill simply by putting the transmission in NEUTRAL and letting gravity act on the vehicle, as the HSA will prevent the vehicle from rolling. Instead, use the appropriate gear for moving in the desired direction.
Towing With HSA
HSA will provide assistance when starting on a grade when pulling a trailer.
WARNING!
• If you use a trailer brake controller with your trailer, your trailer brakes may be activated and deactivated with the brake switch. If so, when the brake pedal is released there may not be enough brake pressure to hold the vehicle and trailer on a hill and this could cause a collision with another vehicle or object behind you. In order to avoid rolling down the hill while resuming acceleration, manually activate the trailer brake prior to releasing the brake pedal. Always remember the driver is responsible for braking the vehicle.
• HSA is not a parking brake. Always apply the parking brake fully when leaving your vehicle. Also, be certain to leave the transmission in PARK.
• Failure to follow these warnings may cause the vehicle to roll down the incline and could collide with another vehicle, object or person, and cause serious or fatal injury. Always remember to use the parking brake while parking on a hill and that the driver is responsible for braking the vehicle.
NOTE: The HSA system may also be turned on and off if the vehicle is equipped with the Electronic Vehicle Information Center (EVIC). Refer to "Electronic Vehicle Information Center (EVIC)" in "Understanding Your Instrument Panel" for further information.
HSA Off
If you wish to turn off the HSA system, follow this procedure:
1. Start with the engine off and vehicle in PARK (automatic transmission) or NEUTRAL with clutch out (manual transmission) with wheels straight. Apply parking brake on manual transmission vehicle.
2. Start the engine.
3. With the engine running, the brake applied, and the clutch out, rotate the steering wheel 180° counterclockwise from center.
4. Press the ESC OFF switch four times within twenty seconds.
5. Rotate the steering wheel 360° clockwise (180° clockwise from center).
6. Cycle ignition switch OFF then ON.
7. If the sequence was completed properly, the "ESC Activation/Malfunction Indicator Light" will blink several times to confirm HSA is off.
Steps 1-7 must be completed within 90 seconds to turn off HSA. Repeat steps 1-7 to re-enable HSA functionality.
I once mistook the brake pedal in my WK2 for the clutch pedal, gently rolling up to a red light, I pushed the brake pedal to the floor thinking it was the clutch. I was only going about 20 mph or so but went to 0 mph very quickly. Scared the you know what outta my wife. Thankfully nobody was behind me.
Just noticed the hill start assist now holds on hills indefinitely - maybe there has been a change/update during a recent service? Very strange.....
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