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 1Secondary Parameters | Execution condition | Soaking time | ≥ 21600 s | Block heater judgment | Completed | Block heater operation | Not in operation | Diagnosis 2Secondary 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 1Engine coolant temperature °C (°F) | −20 (−4) | −10 (14) | 0 (32) | 10 (50) | 20 (68) | Intake air amount sum value (g (oz)) | 50000 (1763.5) | 7400 (261) | 6600 (232.78) | 5800 (204.57) | 5000 (176.35) | Map 2Engine coolant temperature °C (°F) | −30 (−22) | 0 (32) | 10 (50) | 20 (68) | Continuous time (s) when vehicle speed is less than 4 km/h (2.5 MPH) | 250 | 40 | 32 | 24 | 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 ValueMalfunction 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 3Ambient temperature °C (°F) | −30 (−22) | 30 (86) | 45 (113) | 60 (140) | |Intake air temperature 30 sec. after engine start − Engine coolant temperature at engine start| °C (°F) | 12 (21.6°F) | 12 (21.6°F) | 22 (39.6°F) | 22 (39.6°F) | Map 4Ambient temperature °C (°F) | −30 (−22) | 30 (86) | 45 (113) | 60 (140) | |Intake air temperature 30 sec. after engine start − Ambient air temperature 30 sec. after engine start| °C (°F) | 20 (36°F) | 20 (36°F) | 32 (57.6°F) | 32 (57.6°F) | Time Needed for Diagnosis: Less than 1 second Diagnosis 2 Judge as NG when the following conditions are established. Judgment ValueMalfunction 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. |