B2968
DTC Troubleshooting: B2968, K and AUTO
DTC B2968 or DTC indicator K and AUTO:
A Short in the Humidity Sensor Circuit
1. Clear the DTC 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 K and AUTO indicated?
YES -
Go to step 5.
NO -
Intermittent failure. Check for loose wires or poor connections on the humidity sensor circuit.
5. Check for DTCs.
Are these DTCs also present; B121B or H and A/C ON, and/or B1220 or L and A/C ON, and/or B1234 or B and A/C ON, and/or B1237 or E and A/C ON?
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 Testing and Inspection.
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 B (12P).
10. Check for continuity between climate control unit connector B (12P) terminal No. 8 and body ground.
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 B (12P) terminals No. 7 and No. 8.
Is there continuity?
YES -
Repair a short in the wires between the climate control unit and the humidity sensor.
NO -
Go to step 12.
12. Turn the ignition switch to ON (II), and measure the voltage between climate control unit connector B (12P) terminal No. 8 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 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; with navigation Climate Control Unit Removal/Installation (With Navigation), without navigation Climate Control Unit Removal/Installation (Without Navigation).
13. Turn the ignition switch to LOCK (0), and disconnect climate control unit connector B (12P).
14. Disconnect these items:
- Driver's air mix control motor
- Passenger's air mix control motor
- Recirculation control motor
- Mode control motor
- Humidity/in-car temperature sensor
15. Check for continuity between climate control unit connector B (12P) terminal No. 7 and body ground.
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 16.
16. Turn the ignition switch to ON (II), and measure the voltage between climate control unit connector B (12P) terminal No. 7 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 have also damaged the climate control unit. Repair the short to power before replacing the climate control unit.
NO -
Go to step 17.
17. Turn the ignition switch to LOCK (0).
18. Reconnect climate control unit connector B (12P).
19. Turn the ignition switch to ON (II), and measure the voltage between climate control unit connector B (12P) terminal No. 7 and body ground.
Is there about 5 V?
YES -
Go to step 20.
NO -
Check for loose wires or poor connections at climate control unit connector B (12P). 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; with navigation Climate Control Unit Removal/Installation (With Navigation), without navigation Climate Control Unit Removal/Installation (Without Navigation).
20. While measuring the voltage between climate control unit connector B (12P) terminal No. 7 and body ground, reconnect these items individually and note the voltage reading each time:
- Driver's air mix control motor
- Passenger's air mix control motor
- Recirculation control motor
- Mode control motor
- Humidity/in-car temperature 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; with navigation Climate Control Unit Removal/Installation (With Navigation), without navigation Climate Control Unit Removal/Installation (Without Navigation).
NO -
Replace the component that caused the voltage drop.