HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS) > Diagnostic Procedure for Sensors > IN-VEHICLE SENSOR

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS) > Diagnostic Procedure for Sensors

IN-VEHICLE SENSOR

TROUBLE SYMPTOM:

• Blower fan speed, outlet port and inlet port do not change after turning the AUTO switch to ON

• Failure related to the in-vehicle sensor is detected by self-diagnosis.

WIRING DIAGRAM:

STEP	CHECK	YES	NO
1.CHECK IN-VEHICLE SENSOR. 1) Turn the ignition switch to OFF. 2) Remove the instrument panel lower cover. 3) Disconnect the connector from in-vehicle sensor. 4) Measure the resistance between connector terminals of in-vehicle sensor. Terminals No. 1 — No. 2:	Is the resistance approximately 2.7 kΩ at 20°C (68°F)?		Replace the in-vehicle sensor.
2.CHECK INPUT SIGNAL FOR IN-VEHICLE SENSOR. 1) Turn the ignition switch to ON. 2) Measure the voltage between in-vehicle sensor harness connector terminal and chassis ground. Connector & terminal LHD model: (i55) No. 2 (+) — Chassis ground (−): RHD model: (B314) No. 2 (+) — Chassis ground (−):	Is the voltage approx. 5 V?
3.CHECK AUTO A/C CONTROL MODULE OUTPUT SIGNAL. 1) Turn the ignition switch to OFF. 2) Remove the auto A/C control module. 3) Turn the ignition switch to ON. 4) Measure the voltage between connector terminals of auto A/C control module. Connector & terminal (i49) No. 12 (+) — (i48) No. 16 (−):	Is the voltage approx. 5 V?
4.CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND IN-VEHICLE SENSOR. 1) Turn the ignition switch to OFF. 2) Disconnect the connector from the auto A/C control module. 3) Measure the resistance of harness between auto A/C control module and in-vehicle sensor. Connector & terminal LHD model: (i55) No. 2 — (i49) No. 12: RHD model: (B314) No. 2 — (i49) No. 12:	Is the resistance less than 1 Ω?		Repair the harness between auto A/C control module and in-vehicle sensor.
5.CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND IN-VEHICLE SENSOR. Measure the resistance of harness between auto A/C control module and in-vehicle sensor. Connector & terminal LHD model: (i55) No. 1 — (i48) No. 16: RHD model: (B314) No. 1 — (i48) No. 16:	Is the resistance less than 1 Ω?		Repair the harness between auto A/C control module and in-vehicle sensor.
6.CHECK POOR CONTACT. Check poor contact of auto A/C control module connector.	Is there poor contact of the connector?	Repair the connector.	Replace the auto A/C control module.