Purpose/Function
The hill launch assist (HLA) is a function which assists the driver in accelerating the vehicle on a slope by activating the traction control solenoid valve in the DSC HU/CM when the vehicle begins accelerating on a slope, and maintaining/reducing brake fluid pressure to prevent the vehicle from rolling for a specified time.
The system automatically operates when the vehicle is stopped on a slope of approx. 3 % or more (changes slightly depending on load and vehicle conditions such as tire wear and air pressure). (MTX)
The system automatically operates when the vehicle is stopped on a slope of approx. 6 % or more (changes slightly depending on load and vehicle conditions such as tire wear and air pressure). (ATX)
NOTE:
The shift lever position is in the other than R position, the hill launch assist (HLA) operates on a upslope. (MTX)
The selector lever position is in the D/M position, the hill launch assist (HLA) operates on a upslope. (ATX)
The selector/shift lever position is in the R position, the hill launch assist (HLA) operates on a downslope.
The hill launch assist (HLA) operates constantly without affecting the TCS OFF switch operation.
When the parking brake is applied, the hill launch assist (HLA) does not operate.
When the DSC indicator light illuminates, the hill launch assist (HLA) does not operate.
Structure
The hill launch assist (HLA) constantly controls the brake fluid pressure in accelerating the vehicle on a slope by determining the hill launch assist (HLA) operation based on the signals input from each module via CAN communication, wheel speed signals from the ABS wheel-speed sensor.
Block diagram
Hydraulic circuit diagram
Operation
If all of the following conditions are met while the vehicle is stopped on a slope, the DSC HU/CM performs controls to maintain brake fluid pressure (control the linear control solenoid valve) even if the driver has released the brake pedal.
Hold control
Control conditions (all of the following conditions met):
Engine speed is at a certain value or more
All doors are fully closed
Slope of approx. 3 % or more (MTX)
Slope of approx. 6 % or more (ATX)
Wheel speed is 0 km/h {0 mph}
Parking brake not operated
Accelerator pedal not depressed
Not fail-safe mode is present
Upslope: The selector lever position is in the D/M position (ATX)
Upslope: The shift lever position is in the position other than R (MTX)
Downslope: The selector/shift lever position is in the R position
Brake pedal is depressed and brake fluid pressure is at a certain value or more
Clutch pedal depressed (MTX)
Control description
If all of the control conditions are met, the DSC HU/CM controls the traction control solenoid valve and maintains brake fluid pressure (driver can depress brake pedal more at this time).
If the brake pedal is released, brake fluid pressure (hold-pressure stored in memory) is maintained for a maximum of 2 s.
Release control
Control condition
After the accelerator pedal is depressed, the required engine torque for accelerating vehicle on a slope is produced
Control description
Brake fluid pressure being maintained is lowered depending on produced engine torque.
Slow release control
Control condition (one or more of following conditions are met):
Parking brake applied
Clutch pedal released (MTX)
DSC HU/CM has malfunction (performs slow release control only if solenoid valve control is available)
0.2 s has elapsed on slope of 1.0 % or less
2 s have elapsed with brake pedal released
Control description
Brake fluid pressure being maintained is lowered in 1 s
Fast release control
Control condition
DSC HU/CM has malfunction and solenoid valve control is not available
Control description
Brake fluid pressure being maintained is reduced to 0 kPa {0 mmHg, 0 inHg} immediately
Passenger Compartment Temperature Sensor Inspection [Full Auto Air Conditioner]
1. Measure the temperature around the passenger compartment temperature sensor
and measure the resistance between passenger compartment temperature sensor terminals
A and B.
If the characteristics of the passenger compartment temperature sensor are
not as shown in the graph, replace t ...
Camshaft Position (CMP) Sensor Inspection
Intake CMP Sensor
Visual inspection
CAUTION:
When replacing the CMP sensor, make sure there is no foreign material on
it such as metal shavings. If it is installed with foreign material, the sensor
output signal will malfunction resulting from fluctuation in magnetic flux and
caus ...
Main Relay Control [Skyactiv G 2.0]
Outline
Supplies power to each part by switching the main relay on/off at the optimal
timing according to the vehicle conditions.
Block Diagram
Operation
When the ignition is switched ON, the main relay turns on and electrical
power is supplied to each sensor and devic ...