Auto Idle Stop System Description (With Auto Idle Stop System) (2020 2021)
Overview
System Description
The auto idle stop system is a system that stops and restarts the engine automatically to help maximize fuel economy depending on environmental and vehicle operating conditions. The system can help reduce fuel consumption, idling noise and any emissions. Conditions such as driver's operation, vehicle state and the environment determine if the vehicle can enter auto idle stop.
Basic System Operations
- When the brake pedal is depressed, the vehicle stops and auto idle stop is activated (if conditions are met). During auto idle stop, the auto idle stop indicator (green) indicator turns on in the gauge control module. When you release the brake pedal, the engine starts automatically (if conditions are met).
- The auto idle stop system is executed when the certain conditions are met. Refer to the Available Conditions for Auto Idle Stop.
- If one of the conditions are met, the engine restarts automatically. However, there are conditions that will prohibit the engine to start automatically. Refer to Engine Restart Conditions After Auto Idle Stop and Disable Conditions for the Engine Restart After Auto Idle Stop.
- The driver can cancel the auto idle stop system from operating with the auto idle stop off switch.
- When the system is off, the auto idle stop indicator (amber) in the gauge control module turns on.
Auto Idle Stop Indicator
System Determination Pattern
After the vehicle is turned to the ON mode, the system is activated and starts a constant monitor of various conditions. The system then determines if a auto idle stop or an engine restart (after the engine has stopped) can be executed.
Auto idle stop at full stop (vehicle speed is 0 km/h (0 mph))
Auto Idle Stop Control Signal
The PCM monitors signals from control units, sensors and switches to determine if the vehicle can execute/continue an auto idle stop or if it can restart the engine. When the PCM determines that the auto idle stop can executed, it stops the fuel injection and stops the engine. When it determines an engine restart, it operates the starter and resumes fuel injection to start the engine. If the PCM receives a malfunction signal from a control unit or the conditions are not met, the auto idle stop is not executed.
Transmitting and Received Signals to/from the PCM
| Target unit, sensor and switch | Transmitting Signal | Received Signal | Remarks |
|---|---|---|---|
| Related control units | System malfunction signal* | - | - |
| Idle stop off switch | Auto idle stop cancellation signal | - | - |
*: See detailed information
| Target unit, sensor and switch | Transmitting Signal | Received Signal | Remarks |
|---|---|---|---|
| Hood latch switch | Hood open/close signal | - | - |
| Driver's seat belt switch | Seat belt buckle/unbuckle signal | - | - |
| CVT speed sensor | Vehicle speed/vehicle speed record information | - | - |
| EPS control unit | Steering torque signal | - | - |
| Transmission range switch | Shift position information | - | The signal is sent to the TCM. The TCM sends the determination of the auto idle stop system to the PCM based on the signal. |
| Transmission fluid temperature sensor | Transmission warm-up information | - | The signal is sent to the TCM. The TCM sends the determination of the auto idle stop system to the PCM based on the signal. |
| Auxiliary transmission fluid pump | - |
|
Auxiliary transmission fluid pump is controlled by the TCM. |
| Brake pedal position switch | Brake pedal on/off signal | - | - |
| VSA modulator-control unit |
|
Auto idle stop status information | See detailed information |
| SRS unit | Vehicle inclination angle information | - | - |
| Accelerator pedal module (APP sensor) | Accelerator pedal on/off signal | - | - |
| Engine coolant temperature (ECT) sensor | Engine warm-up information | - | - |
| Barometric pressure (BARO) sensor | Atmospheric pressure (altitude) information | - | - |
| Climate control unit | Auto idle stop permission signal by the climate control system | - | See Detail Information of the Control or Communication Signal |
| Starter | - | Starter operating command signal* | See Detail Information of the Control or Communication Signal |
| 12 volt battery sensor | 12 volt battery status information
|
- | See Detail Information of the Control or Communication Signal |
| DC-DC converter | Unit quality information | - | - |
*: See detailed information
| Target unit, sensor and switch | Transmitting Signal | Received Signal | Remarks |
|---|---|---|---|
| Gauge control module | - | Indicator lamps turn on/off signal | During auto idle stop:
Idle Stop Off Switch ON:
During auto idle stop system failure:
|
| Multi view camera unit | Smart parking assist control signal | Auto idle stop status information | - |
| Driving support system | ACC/LSF system operating information | - | - |
| Injector | - | Fuel injection stop/injection command signal | - |
| Alternator | - | Alternator operating command | - |
*: See detailed information
Detail Information of the Control or Communication Signal
System Malfunction Signal
If a malfunction in the following systems that are related to the auto idle stop have occurred, a warning indicator is turned on or flashes, and the auto idle stop is prohibited. A warning indicator is displayed on the gauge control module (multi-information display), and informs the malfunction to the driver.
System malfunction indications for prohibiting the auto idle stop
| System | Warning indicator | Remarks |
|---|---|---|
| Auto idle stop system | Possible cause:
|
|
| Charging system | Possible cause:
(Auto idle stop indicator is OFF) |
|
| Starter system | ||
| PGM-FI system | Even if this indicator is displayed, the auto idle stop system may be enabled according to the contents of malfunction. | |
| CVT control system | All segments blink. |
| System | Warning indicator | Remarks |
|---|---|---|
| EPS control system | ||
| VSA system (ABS) | Even if this indicator is displayed, the auto idle stop system may be enabled according to the contents of malfunction. | |
| VSA system | Even if this indicator is displayed, the auto idle stop system may be enabled according to the contents of malfunction. | |
| Brake system |
(Red) |
Even if this indicator is displayed, the auto idle stop system may be enabled according to the contents of malfunction. |
| Electric brake booster system | Electric brake booster system malfunction | |
| Automatic brake hold system |
(Amber) |
Even if this indicator is displayed, the auto idle stop system may be enabled according to the contents of malfunction. |
| SRS system | Even if this indicator is displayed, the auto idle stop system may be enabled according to the contents of malfunction. |
Master Cylinder Fluid Pressure Information (lack of brake pedal force)
The master cylinder fluid pressure information is transmitted to the PCM via the VSA modulator-control unit. If the brake pedal force by the driver is insufficient, and if the master cylinder fluid pressure is less than specified value, the auto idle stop is prohibited. In this case, a message is displayed in the multi-information display to inform the driver.
Idle Stop Permission Signal from the Climate Control System
To maintain cabin comfort, the climate control unit transmits the auto idle stop activate, prohibit or engine restart judgment to the PCM based on sensors and switches. When a engine restart request is received from during idle stop, the auto idle stop indicator is turned off and the engine restarts. If the climate control unit malfunctions, the malfunction information is sent to the PCM, and the auto idle stop system warning indicator (orange) blinks.
Transmitting and received signals to/from climate control unit
| Target unit, sensor and switch | Transmitting Signal | Received Signal |
|---|---|---|
| ECON switch | ECON ON/OFF mode selection signal | - |
| Engine coolant temperature (ECT) sensor | Engine warm-up information | - |
| Windshield defrost button/switch | Windshield defrost on/off signal | - |
| Temperature and fan control button/switch (climate control unit) | Cabin temperature and air volume setting information | - |
| Target unit, sensor and switch | Transmitting Signal | Received Signal |
|---|---|---|
| Outside air temperature sensor | Outside air temperature information | - |
| Evaporator temperature sensor/in-car temperature sensor | Air temperature adjustments made before and after | - |
| Humidity sensor | Humidity information in the cabin | - |
| Sunlight sensor | Sunlight information | - |
| PCM | - | Auto idle stop implementation/prohibition determination information from the climate control system. |
Starter Operating Command Signal
The PCM counts the number of times that the start operates and if it exceeds a specified number, prohibits auto idle stop operation. In this case, the indicator on the gauge control module blinks (except when the system is turned off by the driver manually). The starter and the starter cut relay operation number are memorized in the PCM.
12 Volt Battery Status Information
The PCM receives the 12 volt battery status signal and determines the state of quality and its amount of deterioration. When a malfunction is detected, the auto idle stop operation is prohibited and a message is displayed in the multi-information to alert the driver (when the battery is deteriorated).
MID (auto engine idle stop system problem)
If there is a malfunction in the auto idle system and related systems, the auto idle stop indicator will turn on with a message on the multi-information display.
MID (auto engine idle stop unavailable)
If the auto idle system and related systems are normal but auto idle stop operation is prohibited by the system, the following message will be displayed in the multi-information display.
MID (auto engine idle stop: engine will restart soon)
The following message with be displayed right before the engine is restarted by the system when the auto idle stop system is in operation.
DC-DC Converter Unit Quality Information
The DC-DC converter supplies stable power to the vehicle when the battery voltage drops during engine restart. If there is a malfunction in the DC-DC converter, a signal is sent to the PCM and either prohibits the auto idle stop operation or engine restart. If the DC-DC converter malfunctions during engine restart, the starter operation continues but the stable power that the vehicle would have received from the DC-DC converter is not supplied.
Simple Circuit Diagram for Description
Pressurization Graphic by the DC-DC converter