Auto Idle Stop System Description
- Difficulty Level:
The auto idle stop system effectively stops idling by determining the driver operations, inside and outside environments, and the vehicle conditions when the vehicle stops as the engine is already warm. The auto idle stop system can improve the fuel efficiency and reduce the idling noise.
The auto idle stop is enabled when shifting into neutral and releasing the clutch pedal with the vehicle stop. While idling stops, the auto idle stop indicator (green) is indicated on the gauge control module (tach).
The engine restarts automatically after stepping on the clutch pedal.
Also the engine does automatically (without stepping on the clutch pedal) by the driver operation, environment in the cabin/outside of the vehicle, and the vehicle conditions.
When the driver's operation is needed to restart the engine.
The following shows the flow chart for the auto idle stop system control.
The auto idle stop system determines whether the idling stop or restarting engine is needed from informations how the driver's operation, environments in the cabin/outside of the vehicle, and the vehicle conditions are.
* Civic Tourer Shown but same principle to the CTR
At auto idle stop
The engine control module (ECM) determines whether activating the auto idle stop or not by signals from each unit, sensor, and switch.
When the ECM determines that the conditions are met for the auto idle stop system, it stops the engine by cutting the fuel injection.
While the auto idle stop is operating, the auto idle stop indicator (green) on the gauge control module (tach) lights, and the low oil pressure indicator and the charging system indicator go off.
After the vehicle speed condition is met, moving the shift lever to neutral and releasing the clutch pedal to stop the engine automatically. Step on the clutch pedal to restart the engine.
The ECM determines engine restarting by signals from each unit, sensor, and switch. According to the signal, the ECM restarts the engine by resuming fuel injection and driving the starter motor.
With Climate Control
To keep the comfort in the cabin during the auto idle stop, the climate control unit sends the signals to the ECM, that are sent from each sensor and switch. Those are "enable to idle stop", "disable to idle stop", "need to engine restart".
When the climate control unit malfunctions, malfunction information is transmitted to the ECM and auto idle stop indicator (amber) lights.
When the ECM is requested to restart the engine during auto idle stop from the climate control unit, the auto idle stop indicator
Battery Deterioration Detection
The ECM retrieves the information which are the battery internal resistance, current, and voltage via the LIN communication.
The ECM detects the battery deterioration condition based on the received information. If the ECM decides the battery is deteriorated, it disables the auto idle stop.
After replacing the battery, reset the battery internal resistance value by the battery internal resistance reset procedure.
The battery sensor detects the battery current, voltage, and internal resistance, and then transmits the signals to the ECM. The ECM judges the permission of the auto idle stop by signals transmitted from the battery sensor.
Number of Starter Operations
The ECM counts the number of starter operations.
If the number of starter operations exceeds the setting limit, the auto idle stop is disabled, and the auto idle stop indicator (amber)* in the gauge control module (tach) comes on. In this case, the starter motor, starter cut relay 1, and starter cut relay 2 need to be replaced, and it is needed to clear the counter of "STARTER and STARTER CUT RELAY" with the HDS.
When replacing the ECM, the number of starter operations stored in the previous ECM needs to be transferred to the new ECM.
*: When the auto idle stop system is turned off by the idle stop off switch, the auto idle stop indicator (amber) does not come on.
With DC-DC Converter
The DC-DC converter boosts the voltage to compensate for a voltage loss that occurs when restarting the engine after the auto idle stop in order to provide a stable power supply to each electrical component of the vehicle.
The DC-DC converter is activated by a start signal from the ECM.
Malfunctions related to the Auto Idle Stop System
When the system related to the auto idle stop system (refer to the following) is fault, the auto idle stop system is prohibited.
If the following indicator comes on, do the troubleshooting for each related system.