Auto Idle Stop System Description - Operating Condition

Disable Conditions for Auto Idle Stop 

When any of the following conditions are met, auto idle stop is disabled.

Idle Stop Disable Conditions	Parameter (HDS)
Vehicle Speed 10 km/h (6 mph) or more. More than 0 km/h (0 mph) with brake pedal fully released (brake pedal position switch OFF). Does not exceed 12 km/h (7 mph) in forward gears. Does not exceed 12 km/h (7 mph) after reverse gear use.	VEHICLE SPEED
Transmission Shift position is not D or N. Start clutch calibration is not complete. CVT fluid temperature is not over definite value. Pulley ratio is less than 2.1. Uphill judgment. Slight creep disable. Shift position is not judged.	A/T D SWITCH A/T N SWITCH LEARN CONDITION PULLEY RATIO
VSACAS control disabled.
Brake Pedal Brake pedal not pressed (Brake pedal stroke sensor CLOSE, brake pedal position switch OFF). Sudden braking. Brake pedal stroke sensor signal does not indicate OPEN/CLOSE after exceeding 18 km/h (11 mph). Brake pedal position switch does not indicate after exceeding 18 km/h (11 mph). NOTE: Brake pedal pressing is detected by brake pedal position switch input signal (ON with pedal pressed). Brake pedal pressing is detected by brake pedal stroke sensor input signal (OPEN with pedal pressed).	BRAKE PEDAL STROKE SENSOR BRAKE SWITCH AUTO IDLE STOP DOES NOT OCCUR (BRAKE PEDAL STROKE SENSOR)
Accelerator Pedal Accelerator pedal is pressed (APP sensor is more than 0.2 %).	APP SENSOR
Engine Coolant Temperature and Outside Air Temperature; Engine coolant temperature does not exceed specified value, depending on outside air temperature, A/C system use, and if ECON mode is on or off.	ENGINE COOLANT TEMPERATURE IAT SENSOR
ECM A related DTC is stored. Communication problem with any control unit related to auto idle stop. For 50 seconds after engine starting.

Idle Stop Disable Conditions	Parameter (HDS)
IMA System Battery module SOC indicator shows two segments less. Motor power inverter (MPI) temperature is 106 °C [379 °F] or more. Battery module power is regulated to 6.6 kW or less. IMA motor rotor calibration is not completed. A related DTC is stored. PUC failure requires Idle Stop disable.	SOC MPI TEMPERATURE MOTOR ASSIST UNIT CMD ASSIST POWER LIMIT OF IMA BATTERY BY TEMPERATURE ASSIST POWER LIMIT OF IMA BATTERY BY VOLTAGE MOTOR ROTOR POSITION CALIBRATION STATE
Climate Control System Outside air temperature is -20 °C [-4 °F] or less. A/C inverter condition signal is started as whether Asleep or Wait. A/C inverter failure signal. IMA-CAN failure signal. The electrical water pump failed, the blower motor is activated, outside air temperature is less than 20 °C and air flow is passing through the heat core. No water temperature sensor signal for a certain period of time.	AUTO IDLE STOP DOES NOT OCCUR (A/C)

Engine Restart Conditions After Auto Idle Stop 

When any of the following conditions are met, the engine restarts after idle stop.

Engine Restart Conditions	Parameter (HDS)
Engine Start Switch; Shift position is in N, and ignition switch is turned to START (III).	STARTER SWITCH
Vehicle Speed Acceleration exceeds 20 km/h (12 mph). (parameter is in case of brake input failure) Vehicle speed pulse generated during idle stop.	VEHICLE SPEED
Transmission shift position is P or R.	A/T P SWITCH A/T R SWITCH
Brake System; Brake pedal is released.	BRAKE SWITCH
Accelerator Pedal Accelerator pedal is pressed (APP sensor is more than 0.2 %).	APP SENSOR
IMA System Battery module SOC indicator shows two segments or less.	SOC
Climate Control System Defogger switch is ON. The outside temperature is less than 23 degrees below zero Celsius. The control unit determines that the set temperature cannot be maintained. The A/C inverter condition signal is stated as either ASLEEP or WAIT. With an electrical water pump failure, the blower motor is activated, the outside air temperature less than 20 °C and air flow is directed through the heat core. A/C inverter failure signal. IMA-CAN failure signal. No water temperature sensor signal for a certain period of time.	IDLE STOP DISABLE DTC

Battery module SOC 

When the MCM determines that the remaining battery module state-of-charge (SOC) is within the idle stop enable area, it allows auto idle stop. When the battery module SOC goes below the idle stop enable area during idle stop, the MCM requests an engine restart from the ECM. To confirm the battery module SOC, use the HDS data list. An approximate SOC can also be determined by counting the segments in the battery module SOC indicator.

Courtesy of HONDA, U.S.A., INC.

Battery module output 

The MCM monitors the temperature of the battery module with the battery module temperature sensors. If the output of the battery module is within the idle stop enable area, the MCM allows auto idle stop. If the battery module enters the idle stop disable area, the MCM disables auto idle stop.

Courtesy of HONDA, U.S.A., INC.

Outside air temperature and engine coolant temperature 

This chart shows how Ambient Air and Coolant Temperature affects idle stop. The function is disabled the white area and enabled above it.

Ambient and Coolant Temperature 

Courtesy of HONDA, U.S.A., INC.

Climate Control Over-ride 

In addition, the climate control system can over-ride the PCM and suspend Auto Idle Stop. If the temperatures fall within the highlighted area, Auto Idle Stop suspends if cabin heating or cooling needs require the engine to idle.

Courtesy of HONDA, U.S.A., INC.