Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc p0072 ambient air temperature sensor circuit "a" low

Subaru Legacy BN/BS (2015-2019) Service Manual / Engine (diagnostics)(h4do) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc p0072 ambient air temperature sensor circuit "a" low

DTC DETECTING CONDITION:

Immediately at fault recognition

STEP	CHECK	YES	NO
1.CHECK DTC. Check for DTC. Read Diagnostic Trouble Code (DTC)	Is P0072 or P0073 displayed in «Present fault»-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0072 AMBIENT AIR TEMPERATURE SENSOR CIRCUIT "A" LOW	Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again. NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2.CHECK COMBINATION METER. Check the combination meter system. Basic Diagnostic Procedure	Is the combination meter system normal-	Repair the poor contact of ECM connector.	Replace the combination meter system. Combination Meter

1. OUTLINE OF DIAGNOSIS

Detect the open or short circuit of ambient temperature sensor.

Judge as NG if out of specification.

2. COMPONENT DESCRIPTION

Ambient temperature sensor is connected to combination meter. ECM receives the data of ambient temperature sensor via CAN communication with combination meter.

(1)

Ambient sensor

(2)

Resistance value (k-)

(3)

Ambient air temperature (°C (°F))

3. EXECUTION CONDITION

Secondary Parameters	Execution condition
Battery voltage	≥ 10.9 V

4. GENERAL DRIVING CYCLE

Always perform the diagnosis continuously.

5. DIAGNOSTIC METHOD

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
Output voltage	< 0.42 V

Time Needed for Diagnosis: 2500 ms

Malfunction Indicator Light Illumination: Illuminates as soon as a malfunction occurs.

Dtc p0073 ambient air temperature sensor circuit "a" high

NOTE:For the diagnostic procedure, refer to DTC P0072. Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0072 AMBIENT AIR TEMPERATURE SENSOR CIRCUIT "A" LOW1. OUTLINE OF DIAGNOSISDetect ...

Dtc p0071 ambient air temperature sensor circuit "a" range/performance

DTC DETECTING CONDITION:Detected when two consecutive driving cycles with fault occur.CAUTION:After servicing or replacing faulty parts, perform Clear Memory Mode Clear Memory Mode > OPERATION, and I ...

Other materials:

Removal
CAUTION:Vehicle components are extremely hot after driving. Be wary of receiving burns from heated parts.1. Disconnect the ground terminal from battery sensor. NOTE2. Lift up the vehicle.3. Remove the under cover. Front Under Cover > REMOVAL4. Disconnect the front oxygen (A/F) sensor connector (A) ...