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HOMESERVICE MANUALSACURA2018MDX BASEREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE MECHANICALMECHANICALENGINE CONTROL AND ENGINE MECHANICAL - SERVICE, TESTING AND TROUBLESHOOTING (EXCEPT HYBRID)DESCRIPTION & OPERATIONAUTO IDLE STOP SYSTEM DESCRIPTION - OPERATION CONDITIONS

2018 Acura MDX Base

Auto Idle Stop System Description - Operation Conditions

2018 Acura MDX BaseSECTION Auto Idle Stop System Description - Operation Conditions

Auto Idle Stop System Operation Conditions

Disable Conditions for Auto Idle Stop

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

NOTE: Check the DTCs of all systems before doing the inspection of the auto idle stop.

Idle Stop Disable Conditions		HDS		AUTO IDLE STOP INDICATOR (amber)
Item	Conditions	Parameter	Menu	AUTO IDLE STOP INDICATOR (amber)
Idle Stop Off Switch	Idle stop off switch is ON.	IDLE STOP INHIBIT (IDLE STOP CANCEL SWITCH)	PGM FI	ON
Hood	Hood is open. (Security hood switch is OFF)	IDLE STOP INHIBIT (HOOD OPEN)	PGM FI	-
Driver's Seat Belt Buckle Switch	Driver seat belt is not latched.	IDLE STOP INHIBIT (SEAT BELT UNFASTENED)	PGM FI	-
Steering Wheel	Steering wheel is operated ('19-20Except Mexico model).	IDLE STOP INHIBIT (EPS UNIT)	PGM FI	-
Vehicle Speed	More than 0 mph (0 km/h).	VEHICLE SPEED	PGM FI	-
		VEHICLE SPEED	AT	-
		LEFT FRONT WHEEL SPEED	ABS VSA	-
		RIGHT FRONT WHEEL SPEED	ABS VSA	-
		LEFT REAR WHEEL SPEED	ABS VSA	-
		RIGHT REAR WHEEL SPEED	ABS VSA	-
	Does not exceed 3 mph (5 km/h) after engine start or engine restart from idle stop. : Does not exceed 9.3 mph (15 km/h) when the acceleration and deceleration are repeated while driving at low speed.	-	-	-
Transmission	Auto Idle Stop Disable Conditions Determination	IDLE STOP INHIBIT (AT/CVT: PRECONDITION)	PGM FI	-
	Shift position is not D.	A/T D SWITCH	AT	-
	Transmission fluid temperature is too high (more than 230 °F (110 °C)) or too low (less than 68 °F (20 °C)).	ATF Temperature	AT	-
VSA	VSA system is operated.	IDLE STOP INHIBIT (ABS/VSA UNIT)	PGM FI	-
VSA	VSA sensor neutral position memorization is not completed.	VSA ADJUSTMENT	ABS VSA	-
Brake Pedal	Brake pedal is not pressed (Brake pedal pressed: BRAKE SWITCH is ON/IDLE STOP SW is OPEN).*: Except during ACC/LSF system.	CRUISE BRAKE SW/IDLE STOP SW	PGM FI	-
		BRAKE SWITCH	PGM FI	-
	Brake pedal pressing is weak (brake system is low oil pressure).	-	-	-

NOTE:

If some DTCs are indicated, the auto idle stop system may be disabled.
If the auto idle stop indicator (amber) blinks, the number of starter motor operations exceeded the setting limit, the auto idle stop indicator comes on when the auto idle stop system is turned to off by pressing the idle stop off switch.

Idle Stop Disable Conditions		HDS		AUTO IDLE STOP INDICATOR (amber)
Item	Conditions	Parameter	Menu	AUTO IDLE STOP INDICATOR (amber)
Accelerator Pedal	Accelerator pedal is pressed.	APP SENSOR	PGM FI	-
Incline	Uphill or downhill determination	IDLE STOP INHIBIT (INCLINED STATE)	PGM FI	-
PGM-FI	Operation number of starter exceed specified value.	-	-	Blinks
	PCM idle learn procedure is not completed.	IDLE LEARN	PGM FI	-
	Engine coolant temperature is too high (more than 230 °F (110 °C)) or too low (less than 149 °F (65 °C)).	ECT SENSOR 1	PGM FI	-
Brake Booster Pressure	Auto Idle Stop Disable Conditions Determination	IDLE STOP INHIBIT (BRAKE SYSTEM)	PGM FI	-
Brake Booster Pressure	Brake booster pressure is low (almost 0 kPa (0 inHg, 0 mmHg) than -32.9 kPa(-9.7 inHg, -247 mmHg)) . : It is a variable depending on the atmospheric pressure.	BRAKE BOOSTER PRESSURE SENSOR	BRAKE SYSTEM	-
Climate Control System	Auto Idle Stop Disable Conditions Determination(While the climate control system is on)	IDLE STOP INHIBIT (HVAC)	PGM FI	-
	Windshield defrost button is ON.	-	-	-
	Temperature setting is Hi or Lo.	-	-	-
	On demand multi-use display (ODMD) (TM) (blower fan display) is more than 5 segments.	-	-	-
	Outside air temperature is 104 °F (40 °C) or above.	-	-	-
	Outside air temperature is -4 °F (-20 °C) or less.	-	-	-
	Windshield fogging is detected (based on outside air temperature, humidity, and other conditions).	-	-	-
	When the cabin is uncomfortable due to high or low interior air temperature or high humidity.	-	-	-
	Rear air conditioning is ON.	-	-	-
DC-DC Converter	Auto Idle Stop Disable Conditions Determination	IDLE STOP INHIBIT (DC-DC CONVERTER)	PGM FI	-
DC-DC Converter	DC-DC converter temperature failure/DC-DC converter internal failure/DC-DC converter input voltage failure.	-	-	-
12 Volt Battery	Auto Idle Stop Disable Conditions Determination	IDLE STOP INHIBIT (BATTERY MANAGEMENT SYSTEM)	PGM FI	-
12 Volt Battery	Temperature of the 12 volt battery is less than 14 °F (-10 °C).	ESTIMATED BATTERY TEMPERATURE (BATTERY SENSOR)	PGM FI	-

NOTE:

If some DTCs are indicated, the auto idle stop system may be disabled.
If the auto idle stop indicator (amber) blinks, the number of starter motor operations exceeded the setting limit, the auto idle stop indicator comes on when the auto idle stop system is turned to off by pressing the idle stop off switch.

Idle Stop Disable Conditions		HDS		AUTO IDLE STOP INDICATOR (amber)
Item	Conditions	Parameter	Menu	AUTO IDLE STOP INDICATOR (amber)
	12 volt battery is deteriorated.	IDLE STOP INHIBIT (BATTERY DETERIORATION)	PGM FI	-
	12 volt battery voltage is insufficient.	IDLE STOP INHIBIT (LOW BATTERY VOLTAGE)	PGM FI	-

NOTE:

If some DTCs are indicated, the auto idle stop system may be disabled.
If the auto idle stop indicator (amber) blinks, the number of starter motor operations exceeded the setting limit, the auto idle stop indicator comes on when the auto idle stop system is turned to off by pressing the idle stop off switch.

Engine Restart Conditions After Auto Idle Stop

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

Engine Restart Conditions		HDS
Item	Conditions	Parameter	Menu
Idle Stop Off Switch	Idle stop off switch is turned from OFF to ON.	IDLE STOP INHIBIT (IDLE STOP CANCEL SWITCH)	PGM FI
Driver's Seat Belt Buckle Switch	Driver's seat belt is removed.	IDLE STOP INHIBIT (SEAT BELT UNFASTENED)	PGM FI
Adaptive Cruise Control (ACC) System	ACC/LSF system operating state is changed (turned ON to OFF)	-	-
Adaptive Cruise Control (ACC) System	When the ACC/LSF system judges the vehicle is starting	-	-
Steering Wheel	Steering wheel is operated.	IDLE STOP INHIBIT (EPS UNIT)	PGM FI
Vehicle Speed	0.6 mph (1 km/h) or more.	VEHICLE SPEED	PGM FI
		VEHICLE SPEED	AT
		LEFT FRONT WHEEL SPEED	ABS VSA
		RIGHT FRONT WHEEL SPEED	ABS VSA
		LEFT REAR WHEEL SPEED	ABS VSA
		RIGHT REAR WHEEL SPEED	ABS VSA
Transmission	Shift to any driving position other than D, or shift to D from N.	A/T N SWITCH A/T D SWITCH	ATAT
	Transmission fluid temperature is too high (more than 230 °F (110 °C)) or too low (less than 68 °F (20 °C)).	ATF Temperature	AT
Brake Pedal	Brake pedal is released during auto idle stop (Brake pedal released: BRAKE SWITCH is OFF/IDLE STOP SW is CLOSE) (When not operating ACC/LSF system (with ACC/LSF system)).	CRUISE BRAKE SW/IDLE STOP SW BRAKE SWITCH	PGM FI PGM FI
Accelerator Pedal	Accelerator pedal is pressed.	APP SENSOR	PGM FI

Engine Restart Conditions		HDS
Item	Conditions	Parameter	Menu
Brake Booster Pressure	Engine Restart Determination	IDLE STOP INHIBIT (BRAKE SYSTEM)	PGM FI
Brake Booster Pressure	Brake booster pressure became low (almost 0 kPa (0 inHg, 0 mmHg) than -30.2 kPa (-8.9 inHg, -227 mmHg)). : It is a variable depending on the atmospheric pressure.	BRAKE BOOSTER PRESSURE SENSOR	BRAKE SYSTEM
Climate Control System	Engine Restart Determination	IDLE STOP INHIBIT (HVAC)	PGM FI
	Windshield defrost button is ON.	-	-
	Selected system temperature is colder or warmer than the outside air temperature.	-	-
	Rear air conditioning is ON.	-	-
12 Volt Battery	12 volt battery voltage decrease during auto idle stop.	IDLE STOP INHIBIT (LOW BATTERY VOLTAGE)	PGM FI

Engine Restart Disable Conditions

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

Engine Restart Disable Conditions		HDS
Item	Conditions	Parameter	Menu
Hood	Hood is open. (Security hood switch is OFF)	IDLE STOP INHIBIT (HOOD OPEN)	PGM FI
Starter	Engine cranks long time of 5 seconds or more.	-	-
	Engine does not crank.	-	-
DC-DC Converter	Engine Restart Disable Determination	IDLE STOP INHIBIT (DC-DC CONVERTER)	PGM FI
DC-DC Converter	DC-DC converter temperature failure/DC-DC converter internal failure/DC-DC converter input voltage failure.	-	-

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.