ISG (Idle Stop & Go) System

Components and Component Location

Component Location

1. Battery Sensor 2. Brake Booster Vacuum Pressure Sensor (BBVPS) 3. AGM Battery 4. DC-DC Converter 5. ISG Switch 6. Generator

7. Starter Motor 8. Neutral Switch 9. Clutch Switch 10. Door Switch 11. Seat Belt Switch 12. Hood Switch

1. Battery Sensor 3. AGM Battery	2. Brake Booster Vacuum Pressure Sensor (BBVPS)
4. DC-DC Converter	5. ISG Switch
6. Alternator	7. Starter Motor
8. Neutral Switch	9. Clutch Switch
10. Door Switch	11. Seat Belt Switch
12. Hood Switch

Description and Operation

Description

The Idle Stop & Go (ISG) system turns the engine off when the vehicle stops, and then restarts the engine when the accelerator pedal is depressed. It temporarily stops the engine while waiting at a signal or in idle to improve fuel economy and reduce exhaust emissions. However, the ISG system may not operate if the engine oil or ambient temperature is too low, or if the 12 V battery voltage is too low. The system can be deactivated by pressing the ISG OFF switch when the driver does not wish to use the ISG system. Typical scenario: engine stop at a red traffic light or in stop-and-go traffic.

1. 1
   The vehicle is moving.
2. 2
   Gear engaged. Accelerator pedal depressed.
3. 3
   Engine running.
4. 4
   Driver brakes until the vehicle comes to a complete stop.
5. 5
   The driver shifts into neutral and releases the clutch pedal.
6. 6
   The engine stops. The "AUTO STOP" indicator illuminates on the instrument cluster.
7. 7
   Driver wants to continue driving.
8. 8
   The driver depresses the clutch pedal. The engine starts.
9. 9
   The transmission can be shifted into gear and the journey can be continued. The "AUTO STOP" indicator goes off.

Circuit Diagrams

ISG Operating Conditions

The ISG function is automatically activated each time the engine is started. The ISG OFF switch can be used to deactivate the function manually until the next ignition cycle. The indicator light illuminates to confirm activation when the switch is pressed.

1. Idle stop condition (Idle → Stop)

▶ Normal condition: neutral position and clutch pedal released.

Required conditions

Engine coolant temperature is not too low (above 45 °C).

No DPF regeneration

No inhibitor for operating strategy or engine malfunction CKPS, CMPS, ECTS, VSS, Battery Sensor, BBVPS, Neutral Switch, Clutch Switch, APS, Injector

Battery charge state is sufficiently high.

No communication line error - LIN, CAN

Vehicle speed below 5 km/h

Vehicle speed exceeds 10 km/h at least once after key-on or idle start

ISG OFF switch OFF

Driver seat belt, driver door and hood are closed.

Battery 2 temperature - 55 °C.

Brake booster pressure is not too low.

Fan not at maximum

2. Idle stop condition (Stop → Start)

▶ Normal condition: neutral position and clutch pedal depressed.

Required conditions

Inhibitor for operating strategy in unsatisfactory condition or engine malfunction CKPS, CMPS, ECTS, VSS, Battery Sensor, Neutral Switch, Clutch Switch, APS

No communication line error - LIN, CAN

Driver seat belt, driver door and hood are closed.

Engine stalled, the transmission was shifted from engaged to neutral and the clutch pedal was depressed.

3. Auto start condition (Stop → Start)

The engine will start automatically without driver input if one of the following events occurs: ▶ Normal condition: the transmission is in neutral and the clutch pedal is released.

Required conditions

No inhibitor condition for operating strategy TPS, CKPS, CMPS, ECTS, VSS, Battery Sensor, BBVPS, Neutral Switch, Clutch Switch

Brake booster vacuum pressure is low.

When battery charge level is low.

After A/C is turned on, a certain time has elapsed.

Vehicle speed greater than 5 km/h on a downhill grade.

Maximum fan speed

Troubleshooting

Troubleshooting

If the ISG function does not operate even though no DTC is stored, inspect the ISG system as described below. KDS displays the current ISG function data for inspection.