DTC B2968 or DTC indicator B and Windshield Defrost: A Short in the Humidity Sensor Circuit

WARNING: This page is about a different car, the 2011 Acura TL, 2010 Acura TL, and 2009 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.

Clear the DTC with the HDS
Turn the ignition switch to LOCK (0), and then back to ON (II), or press the engine start/stop button to select the OFF mode and then the ON mode
Do the self-diagnostic with the HDS (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITH THE HDS ) or the climate control unit (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITHOUT THE HDS )
Check for DTCs
Is DTC B2968 or B and WINDSHIELD DEFROST indicated?

YES -Go to step 5

NO -Intermittent failure Check for loose wires or poor connections on the humidity sensor circuit
Check for DTCs
Are these DTCs also present, B1234 or K and AUTO, and/or B1237 or N and AUTO, and/or B2980 or F and WINDSHIELD DEFROST?

YES -Go to step 13

NO -Go to step 6
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
Remove the humidity/in-car temperature sensor (see HUMIDITY/IN-CAR TEMPERATURE SENSOR REPLACEMENT ), and test it (see HUMIDITY/IN-CAR TEMPERATURE SENSOR TEST )
Is the humidity sensor OK?

YES -Go to step 8

NO -Replace the humidity/in-car temperature sensor
Disconnect the humidity/in-car temperature sensor 4P connector
Disconnect climate control unit connector C (20P)
Check for continuity between body ground and climate control unit connector C (20P) terminal No 12

Fig 1: Checking Continuity Between Body Ground And Climate Control Unit Connector C (20P) Terminal 12
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair short to body ground in the wire between the climate control unit and the humidity sensor

NO -Go to step 11
Check for continuity between climate control unit connector C (20P) terminals No 2 and No 12

Fig 2: Checking Continuity Between Climate Control Unit Connector C (20P) Terminals 2 And 12
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair short in the wires

NO -Go to step 12
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode, and measure the voltage between climate control unit connector C (20P) terminal No 12 and body ground

Fig 3: Measuring Voltage Between Climate Control Unit Connector C (20P) Terminal 12 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there any voltage?

YES -Repair short to power in the wire between the climate control unit and the humidity sensor This short may also damage the climate control unit Repair the short to power before replacing the climate control unit

NO -Substitute a known-good climate control unit, and recheck If the symptom/indication goes away, replace the original climate control unit (see Climate Control Unit Removal/Installation )
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode, and disconnect climate control unit connector C (20P)
Disconnect these items
- Driver's air mix control motor
- Passenger's air mix control motor
- Humidity/in-car temperature sensor
- A/C pressure sensor
Check for continuity between climate control unit connector C (20P) terminal No 2 and body ground

Fig 4: Checking Continuity Between Climate Control Unit Connector C (20P) Terminal 2 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair short to body ground in the wire

NO -Go to step 16
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode, and measure the voltage between the same terminal and body ground

Fig 5: Measuring Voltage Between Climate Control Unit Connector C (20P) Terminal 2 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there any voltage?

YES -Repair short to power in the wire This short may have also damaged the climate control unit Repair the short to power before replacing the climate control unit

NO -Go to step 17
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
Reconnect the climate control unit connector C (20P)
Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode and measure the voltage between climate control unit connector C (20P) terminal No 2 and body ground

Fig 6: Measuring Voltage Between Climate Control Unit Connector C (20P) Terminal 2 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 5V?

YES -Go to step 20

NO -Check for a loose wire or poor connection at climate control unit connector C (20P) If the connection is good, substitute a known-good climate control unit and recheck If the symptom/indication goes away, replace the original climate control unit (see Climate Control Unit Removal/Installation )
While measuring the voltage as described in step 19, reconnect these items individually and note the voltage reading each time
- Driver's air mix control motor
- Passenger's air mix control motor
- Humidity/in-car temperature sensor
- A/C pressure sensor
Fig 7: Measuring Voltage Between Climate Control Unit Connector C (20P) Terminal 2 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Does the voltage remain at about 5 V?

YES -Substitute a known-good climate control unit, and recheck If the symptom/indication goes away, replace the original climate control unit (see Climate Control Unit Removal/Installation )

NO -Replace the component that caused the voltage drop