DRIVE-BY-WIRE CONTROL OPERATION [L8, LF, L5]

id014046170600


Idle Speed Control

•  Controls the throttle valve opening angle so that it is close to the target idle speed calculated by the PCM.
•  The PCM calculates the target throttle opening angle by adding each type of correction to the basic duty value which is the basis of the throttle valve opening angle, and then sends a duty signal to the throttle valve actuator. The basic duty value is determined by the target engine speed.
•  Each type of correction is as follows.

Correction

Correction

Purpose

Condition

Amount of Correction
A/C load correction
Prevent drop in engine speed during A/C operation
A/C operation
A/C operation → correction
Electrical load correction
Prevent drop in engine speed during operation of electrical loads
Idling or driving
Electrical load increases → correction increases
Fuel cut recovery decrease correction
Reduce shock during fuel cut recovery
In deceleration fuel cut zone, decrease by set amount
In deceleration fuel cut zone → correction by set amount
Accelerate warm up correction
Accelerate activation of catalytic converter
Idling when engine speed >1,000 rpm and atmospheric pressure >72.0 kPa {540 mmHg, 21.3 inHg}, according ECT
ECT decreases → correction increases
D range correction
Prevent drop in engine speed during shift into D position
Input of D range signal (TR switch)
Difference between engine speed and turbine speed signal decreases → correction increases
Dashpot correction
Prevent drop in engine speed caused by insufficient air during deceleration
Deceleration
Engine speed increases → correction increases
Starting correction
Prevent drop in engine speed during starting
Cranking or just after engine start
ECT decreases → correction increases
Warm restart correction
Prevent drop in engine speed during warm restoring
Cranking when ECT above 60°C {140 °F}
IAT above 50°C {122 °F}→ increases correction
Closed loop correction A
Make engine speed approach target engine speed
Engine speed while idling (vehicle stopped) deviates from target engine speed (with engine speed above 300 rpm)
Below target engine speed → increase correction
Above target engine speed → decreased correction
Closed loop correction B
When engine speed drops, make engine speed approach target engine speed in zone where closed loop correction A cannot compensate
Engine speed below target engine speed during deceleration (with engine speed above 300 rpm) and when closed loop correction A not active
Difference between engine speed and target engine speed increases → correction increases
Learning correction
Store change in air intake amount caused by differences in each engine and secular change and gives closed loop
Idling when ECT above 70°C {158 °F} and IAT below 75°C {167 °F} (during closed loop correction A)
During idling → average value of closed loop correction A


Accelerator Control

•  Controls the throttle valve opening angle through control of the throttle valve actuator, according to the amount of AP depression.
•  The PCM controls the throttle valve actuator so that the actual throttle valve opening angle is close to the target throttle valve opening angle.
•  The final throttle valve opening angle is determined by the sum of the target throttle opening angle during idling and the target throttle valve opening angle during regular driving.
•  The target throttle valve opening angle during regular driving is determined based on the transmission gear position, the amount of AP depression and the engine speed. If the target throttle opening angle is at the fixed value or less during regular driving, the PCM switches to idle speed control.
•  The PCM sets the throttle valve to the fully-closed position when the ignition switch is on or off and executes the idle position learning function to learn the throttle valve position. Due to this, changes in the throttle valve opening angle due to age deterioration are corrected.
•  When the ignition switch is off, a main relay on request is output and the fully-closed learning function is executed. (See MAIN RELAY CONTROL OPERATION [L8, LF, L5].)

Traction Control

•  The PCM calculates the target throttle valve opening angle by the torque up/down request signal from the TCM (ATX) and ABS/DSC HU/CM.

Cruise Control (Vehicles Equipped With Cruise Control Switch)

•  Calculates the throttle valve opening angle based on the deviation of the actual vehicle speed from the set vehicle speed which was set with the cruise control switch and the throttle valve actuator.
•  The PCM controls the actual vehicle speed so that it is close to the set vehicle speed.
•  The cruise control includes the cruise control operation condition and the cruise control stop condition.

Cruise control operation condition

•  When all of the following conditions are met, execution of the cruise control system is enabled (cruise control standby status).
―  ON switch: ON
―  Vehicle speed: Exceeds 25 km/h {16 mph}


Cruise control stop condition

•  When any of the following conditions are met even while in cruise control, the PCM stops the cruise control and clears the set vehicle speed.
―  Ignition: OFF
―  ON switch: OFF
―  Cruise control related DTCs (P0571:00, P0579:00, P0581:00) detected
•  When any of the following conditions are met even while in cruise control, the PCM stops the cruise control while storing the set vehicle speed.
―  CANSEL switch: ON
―  TR switch: P/N position switch: ON (ATX)
―  Vehicle speed: Less than 20.5 km/h {12.7 mph}
―  Brake switch: ON (brake pedal depressed)
―  The actual vehicle speed is 15 km/h {9.3 mph} or more lower than the set vehicle speed during cruise control (ascending).
―  CPP switch: ON (clutch pedal depressed) (MTX)
―  Neutral switch: ON (neutral position) (MTX)


Cruise control function

•  The cruise control includes accelerating, coasting, resume, tap-down, tap-up and downshift functions.

Function List

Function

Contents
Accelerating
•  When any of the following conditions are met while driving in cruise control and when the SET+ switch is continuously pressed, the PCM gradually increases the set vehicle speed.
―  The SET+ switch is on one time or more during resume operation.
Coasting
•  When the SET- switch is continuously pressed, the PCM gradually decreases the set vehicle speed.
Resume
•  When the RESUME switch signal is input to the PCM during regular driving (cruise control is stopped) and the previously set vehicle speed is stored in the PCM, the PCM sets the set vehicle speed to the previously set vehicle speed and begins control.
Tap down
•  When all of the following conditions are met while driving in cruise control, the PCM decreases the set vehicle speed by 1.6 km/h {1 mph} .
―  SET+ switch off
―  The SET- switch switches from off to on
―  When actual vehicle speed is lower (set vehicle speed +2 km/h {+1.2 mph})
Tap-up
•  When all of the following conditions are met, the PCM increases the set vehicle speed by 1.6 km/h {1 mph} .
―  During cruise control
―  The SET+ switch switches from off to on
―  When actual vehicle speed is lower (set vehicle speed +2 km/h {+1.2 mph})
Downshift
•  When the following conditions are met, a downshift signal is sent to the TCM via CAN.
―  SET+ switch on
―  Target vehicle acceleration is not reached


Excess Engine Speed Control

•  If the engine reaches a high engine speed, the following controls are performed to protect the engine:
1.  To alert the driver that the engine speed has reached a high engine speed, the opening and closing of the throttle valve are repeated at regular intervals.
2.  The engine speed stabilizes at a lower speed than the excessive speed zone.
3.  If the engine speed reaches a high engine speed even if the above procedures are performed, a forced shift-up is performed to lower the engine speed. (AT only)

Excess Vehicle Speed Control

•  If the vehicle reaches a high speed, the throttle valve is closed to keep the vehicle speed below the speed limit.