Short
DTC Troubleshooting: B2968 (A and WINDSHIELD DEFROST)
DTC B2968 or DTC indicator A and WINDSHIELD DEFROST:
A Short in the Humidity Sensor Circuit
1. Clear the DTCs with the HDS.
2. Turn the ignition switch to LOCK (0) and then back to ON (II).
3. Do the self-diagnostic function with the HDS or the climate control unit.
4. Check for DTCs.
Is DTC B2968 or A and WINDSHIELD DEFROST indicated?
YES -
Go to step 5.
NO -
Intermittent failure.�
5. Check for DTCs.
Are these DTCs also present; B1234 or K and AUTO, and/or B1237 or N and AUTO, and/or B1245 or G, and/or B2980 or B and WINDSHIELD DEFROST?
YES -
Go to step 13.
NO -
Go to step 6.
6. Turn the ignition switch to LOCK (0).
7. Remove the humidity/in-car temperature sensor Service and Repair, and test it Humidity/In-Car Temperature Sensor Test.
Is the humidity sensor OK?
YES -
Go to step 8.
NO -
Replace the humidity/in-car temperature sensor Service and Repair.�
8. Disconnect the humidity/in-car temperature sensor 4P connector.
9. Disconnect climate control unit connector A (40P).
10. Check for continuity between body ground and climate control unit connector A (40P) terminal No. 27.
Is there continuity?
YES -
Repair a short to body ground in the wire between the climate control unit and the humidity sensor.�
NO -
Go to step 11.
11. Check for continuity between climate control unit connector A (40P) terminals No. 6 and No. 27.
Is there continuity?
YES -
Repair a short in the wires.�
NO -
Go to step 12.
12. Turn the ignition switch to ON (II), and measure the voltage between climate control unit connector A (40P) terminal No. 27 and body ground.
Is there any voltage?
YES -
Repair a 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 a 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 Climate Control Unit Removal/Installation.�
13. Turn the ignition switch to LOCK (0), and disconnect climate control unit connector A (40P).
14. Disconnect these items:
- Driver's air mix control motor
- Passenger's air mix control motor
- Rear air mix control motor
- Humidity/in-car temperature sensor
- A/C pressure sensor
15. Check for continuity between climate control unit connector A (40P) terminal No. 6 and body ground.
Is there continuity?
YES -
Repair a short to body ground in the wire.�
NO -
Go to step 16.
16. Turn the ignition switch to ON (II), and measure the voltage between the same terminal and body ground.
Is there any voltage?
YES -
Repair a short to power in the wire. This short may have also damaged the climate control unit. Repair a short to power before replacing the climate control unit.�
NO -
Go to step 17.
17. Turn the ignition switch to LOCK (0).
18. Reconnect the climate control unit connector A (40P).
19. Turn the ignition switch to ON (II), and measure the voltage between climate control unit connector A (40P) terminal No. 6 and body ground.
Is there about 5 V?
YES -
Go to step 20.
NO -
Check for a loose wire or poor connection at climate control unit connector A (40P). 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 Climate Control Unit Removal/Installation.�
20. 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
- Rear air mix control motor
- Humidity/in-car temperature sensor
- A/C pressure sensor
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 Climate Control Unit Removal/Installation.�
NO -
Replace the component that caused the voltage drop.�