DTC indicator light A: An Open in the In-car Temperature Sensor Circuit

WARNING: This page is about a different car, the 2003 Acura 3.2CL and 2002 Acura 3.2CL. However, it is still accessible from the selected car via links, so may be relevant.

Remove the in-car temperature sensor (see IN-CAR TEMPERATURE SENSOR REPLACEMENT ).
Measure the resistance between the No. 1 and No. 2 terminals of the in-car temperature sensor.
^* Check for change in resistance by heating or cooling the sensor with a hair drier.

Fig 1: Measuring Resistance Of The In-Car Temperature Sensor & Temperature/Resistance Chart
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is resistance within the specifications shown in chart?
1. YES : Go to step 3.
2. NO : Replace the in-car temperature sensor.
Disconnect climate control unit connector B (20P).
Check for continuity between the No. 5 terminal of climate control unit connector B (20P) and the No. 2 terminal of the in-car temperature sensor 2P connector.

Fig 2: Checking Continuity Between The No. 5 Terminal Of Climate Control Unit Connector B (20P) And The No. 2 Terminal Of The In-Car Temperature Sensor 2P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity ?
1. YES : Go to step 5.
2. NO : Repair open in the wire between the climate control unit and the in-car temperature sensor.
Check for continuity between the No. 15 terminal of climate control unit connector B (20P) and the No. 1 terminal of the in-car temperature sensor 2P connector.
CLIMATE CONTROL UNIT CONNECTOR B (20P)

Fig 3: Checking Continuity Between The No. 15 Terminal Of Climate Control Unit Connector B (20P) And The No. 1 Terminal Of The In-Car Temperature Sensor 2P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity ?
1. YES : Check for loose wires or poor connections at climate control unit connector B (20P) and at the in-car temperature sensor 2P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/ indication goes away, replace the original climate control unit.
2. NO : Repair open in the wire between the climate control unit and the in-car temperature sensor.