Pinpoint Test S: Incorrect/Erratic Function In AUTO Mode

Climate Control System

Pinpoint Tests

Pinpoint Test S: Incorrect/Erratic Function in AUTO Mode

Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number

Normal Operation

Under normal operation, the in-vehicle air temperature sensor receives a ground from the HVAC module through circuit RH111 (GY/BU). A 5-volt reference voltage is supplied to the in-vehicle air temperature sensor from the HVAC module through circuit VH414 (GN/BU). To accurately monitor the cabin air temperature, the in-vehicle air temperature sensor uses an integral fan to draw cabin air to the sensor, inside the instrument panel. The fan is supplied voltage through circuit CBP30 (YE/BU) and ground from circuit GD114 (BK/BU)

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- In-vehicle temperature sensor
- HVAC module



PINPOINT TEST S: INCORRECT/ERRATIC FUNCTION IN AUTO MODE

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S1 CHECK IN-VEHICLE TEMPERATURE SENSOR FAN OPERATION


- Ignition ON.
- Make sure the ambient air temperature is above 2°C (35°F).
- Select PANEL mode.
- Press the A/C button (indicator ON).
- Press the RECIRC button (indicator ON).
- Place a piece of tissue within 25 mm (1 in) of the in-vehicle temperature/humidity sensor opening.
- Is the tissue drawn to the sensor opening?

Yes
GO to S2.

No
GO to S3.

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S2 CHECK THE SENSOR RESISTANCE


- Ignition OFF.
- Disconnect: In-Vehicle Temperature Sensor C233.
- Measure the resistance between the in-vehicle temperature sensor C233 terminals and compare to the table below.









- Is the resistance within the specified values for the temperatures?

Yes
GO to S5.

No
INSTALL a new in-vehicle temperature sensor. TEST the system for normal operation.

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S3 CHECK CIRCUIT CBP30 (YE/BU) FOR VOLTAGE


- Ignition ON.
- Measure the voltage between in-vehicle temperature sensor C233-3, circuit CBP30 (YE/BU), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to S4.

No
VERIFY Smart Junction Box (SJB) fuse 30 (5A) is OK. If OK, REPAIR circuit CBP30 (YE/BU) for an open. TEST the system for normal operation. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short Diagrams By Number.

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S4 CHECK CIRCUIT GD114 (BK/BU) FOR GROUND


- Ignition OFF.
- Measure the resistance between in-vehicle temperature sensor C233-2, circuit GD114 (BK/BU), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
INSTALL a new in-vehicle temperature sensor. TEST the system for normal operation.

No
REPAIR circuit GD114 (BK/BU) for an open. TEST the system for normal operation.

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S5 CHECK THE MODULE CONNECTION


- Inspect the module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.
- Connect and correctly seat all the HVAC module connectors.
- Clear the DTCs.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new HVAC module. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

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