Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc p0111 intake air temperature sensor 1 circuit range/performance bank 1

Subaru Legacy BN/BS (2015-2019) Service Manual / Engine (diagnostics)(h6do) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc p0111 intake air temperature sensor 1 circuit range/performance bank 1

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode Clear Memory Mode > OPERATION, and Inspection Mode Inspection Mode > PROCEDURE.

STEP	CHECK	YES	NO
1.CHECK ENGINE COOLANT TEMPERATURE. 1) Start the engine and warm up completely. 2) Read the value of «Coolant Temp.» using the Subaru Select Monitor or a general scan tool. NOTE: • Subaru Select Monitor For detailed operation procedures, refer to “Read Current Data For Engine”. Subaru Select Monitor • General scan tool For detailed operation procedures, refer to the general scan tool operation manual.	Is the value of «Coolant Temp.» 75°C (167°F) or more-	Replace the mass air flow and intake air temperature sensor. Mass Air Flow and Intake Air Temperature Sensor	Check for DTC P0125. Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0125 INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL

1. OUTLINE OF DIAGNOSIS

Detect the malfunction of the intake air temperature sensor output properties. Using the following two diagnoses, judge as NG when either is NG.

• Diagnosis 1 (correlation diagnosis): After the engine starts after the specified period of soaking time has elapsed, diagnose by correlation between intake air temperature sensor value, engine coolant temperature sensor value and ambient temperature sensor value. Judge as NG when the differences are both above the specified value by comparing between intake air temperature and engine coolant temperature, intake air temperature and ambient air temperature.

• Diagnosis 2 (stuck diagnosis): Judge as NG when intake air temperature does not change under the driving condition where it should change, considering engine condition.

2. COMPONENT DESCRIPTION

(A)	Air

(1)	Air flow sensor	(3)	Resistance value (-)	(4)	Intake air temperature °C (°F)
(2)	Intake air temperature sensor

3. EXECUTION CONDITION

Diagnosis 1

Secondary Parameters	Execution condition
Soaking time	≥ 21600 s
Block heater judgment	Completed
Block heater operation	Not in operation

Diagnosis 2

Secondary Parameters	Execution condition
Battery voltage	≥ 10.9 V
Engine coolant temperature	≥ 75 °C (167 °F)
Intake air amount sum value	≥ Value of Map 1

Number of experiences under conditions below	≥ 3 time(s)
• Continuous time when vehicle speed is less than 4 km/h (2.5 MPH)	≥ Value from Map 2
• Continuous time when vehicle speed is 40 km/h (24.9 MPH) or more, and intake air amount is 10 g/s (0.35 oz/s) or more	≥ 15 s

Map 1

Engine coolant temperature

°C (°F)

−20

(−4)

−10

(14)

(32)

(50)

(68)

Intake air amount sum value (g (oz))

50000 (1763.5)

7400 (261)

6600 (232.78)

5800 (204.57)

5000 (176.35)

Map 2

Engine coolant temperature

°C (°F)

−30

(−22)

(32)

(50)

(68)

Continuous time (s) when vehicle speed is less than 4 km/h (2.5 MPH)

250

4. GENERAL DRIVING CYCLE

• Diagnosis 1: Perform the diagnosis only once after the engine starts after a certain period of soaking time.

• Diagnosis 2: Perform the diagnosis when the vehicle speed condition is met after warming up from a cold condition.

5. DIAGNOSTIC METHOD

Judge as NG when Diagnosis 1 or Diagnosis 2 becomes NG.

Diagnosis 1

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Judgment Value

Malfunction Criteria	Threshold Value
\|Intake air temperature 30 sec. after engine start − Engine coolant temperature at engine start\|	> Value of Map 3
\|Intake air temperature 30 sec. after engine start − Ambient air temperature 30 sec. after engine start\|	> Value of Map 4

Map 3

Ambient temperature

°C (°F)

−30

(−22)

(86)

(113)

(140)

|Intake air temperature 30 sec. after engine start − Engine coolant temperature at engine start|

°C (°F)

(21.6°F)

(39.6°F)

Map 4

Ambient temperature

°C (°F)

−30

(−22)

(86)

(113)

(140)

|Intake air temperature 30 sec. after engine start − Ambient air temperature 30 sec. after engine start|

°C (°F)

(36°F)

(57.6°F)

Time Needed for Diagnosis: Less than 1 second

Diagnosis 2

Judge as NG when the following conditions are established.

Judgment Value

Malfunction Criteria

Threshold Value

Output voltage difference between Max. and Min.

< 0.02 V

(Equivalent to approximately 0.5°C (0.9°F) near 25°C (77°F))

(Equivalent to approximately 0.9°C (1.6°F) near −7°C (19.4°F))

Time Needed for Diagnosis: Less than 1 second

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

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Caution
• When performing any work, always wear work clothes, a work cap and protective shoes. Additionally, wear a helmet, protective goggles, etc. if necessary.• Remove contamination including dirt and corrosion before removal, installation, disassembly or assembly.• Keep the disassemble ...