How to Troubleshoot the Climate Control System
How to Troubleshoot the Climate Control System
Retrieving DTCs (without HDS)
The climate control unit has a self-diagnostic function. To run the self-diagnostic function, do the following:
NOTE: Before troubleshooting the climate control system, refer to B-CAN System Diagnosis Test Mode A Troubleshooting Troubleshooting - B-CAN System Diagnosis Test Mode A, and the communication circuit self-diagnostic function test.
1. Turn the ignition switch to ON (II).
2. Press and hold the OFF button. While holding the OFF button, press the REAR WINDOW DEFOGGER button five times within 10 seconds. Release the OFF button. All the LEDs and LCD segments should blink three times, then the self-diagnostic begins. Wait for about one minute for the self-diagnostic to complete.
NOTE: The blower motor can be run at any speed regardless of what the panel is displaying.
If there is any problem in the system, the temperature indicator will light the AUTO indicator and the segment (A through N) corresponding to the error. The temperature indicator will then alternate every second between displaying "88" (all segments lit) and the error code segment (A through N) and AUTO indicator. To determine the meaning of the DTC, refer to the DTC Troubleshooting Index.
If there are no problems detected, the segments will not illuminate, and the system will appear to be turned off.
Canceling the Self-diagnostic Function
- Turn the ignition switch to LOCK (0) to cancel the self-diagnostic function. After completing repair work, run the self-diagnostic function again to make sure that there are no other malfunctions.
Checking DTCs by DTC Indicator
NOTE: Before troubleshooting the climate control system, refer to B-CAN System Diagnosis Test Mode A Troubleshooting Troubleshooting - B-CAN System Diagnosis Test Mode A.
To retrieve the DTC, you must run the self-diagnostic function. In the case of multiple problems, the respective indicator segments will come on. If indicator segments A, C, D, E, F, G, I, L, N, and AUTO indicator come on at the same time, there may be an open in the common ground wire.
How to Check for DTCs with the HDS
1. Make sure the ignition switch is in LOCK (0).
2. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.
3. Turn the ignition switch to ON (II).
4. Make sure the HDS communicates with the vehicle and the climate control unit. If it doesn't, troubleshoot the DLC circuit Testing and Inspection.
5. Select HVAC/CLIMATE CONTROL in the BODY ELECTRICAL menu.
6. Select DTCs in the HVAC/CLIMATE CONTROL menu.
7. Check for DTCs. If any DTCs are indicated, write down the DTCs, then go to the indicated DTC troubleshooting. If no DTCs are indicated, refer to symptom troubleshooting.
NOTE:
- After troubleshooting, clear the DTCs with the HDS.
- For specific operations, refer to the user's manual that came with the HDS.
Communication circuit self-diagnostic function ('07 EX and EX-L models)
The climate control unit has a communication circuit self-diagnostic function. Perform the following steps to test the communication circuit.
1. Turn the ignition switch to LOCK (0), and then turn to ON (II).
2. At the climate control panel, press and hold the OFF button. While holding the OFF button, press the rear window defogger button five times within 10 seconds. Release the OFF button. All the LEDs and LCD segments should blink three times.
- If none of the LEDs or LCD segments blink, go to climate control panel power and ground circuit troubleshooting Climate Control Panel Power and Ground Circuit Troubleshooting.
- If one or more LEDs or LCD segments do not blink, but at least one LED or LCD segment blinks, replace the climate control panel.
- If all LEDs and LCD segments blink, go to step 3.
3. Turn the ignition switch to LOCK (0), and then turn to ON (II).
4. At the rear control panel, set the REAR FAN CONTROL DIAL to OFF. The REAR TEMPERATURE CONTROL DIAL to Max Cool, and the REAR MODE CONTROL DIAL to select Vent.
5. Press the REAR CONTROL button five times within 10 seconds. The rear control indicator will come on and then go off. The communication circuit self-diagnostic function will then start. The rear control indicator will blink to indicate any problems.
- If no segment other than segment A lights in the climate control panel and the rear climate control indicator does not blink, the communication circuit is OK.
- If any segment other than segment A lights, and/or the rear control indicator blinks, record the segments and/or blinks, and then go to step 6.
Example of indication Pattern (3)
6. Refer to the chart below and perform the appropriate diagnosis for the error indicated by the front fan segments and rear control indicator.
Communication Circuit self-diagnostic Function Test ('07 Touring model and '08-10 EX, EX-L, and Touring models)
The climate control unit has a communication circuit self-diagnostic function. Perform the following steps to test the communication circuit.
1. Turn the ignition switch to LOCK (0), and then turn to ON (II).
2. At the climate control panel, press and hold the OFF button. While holding the OFF button, press the REAR WINDOW DEFOGGER button five times within 10 seconds. Release the OFF button. All the LEDs and LCD segments should blink three times.
- If none of the LEDs or LCD segments blink, go to climate control panel power and ground circuit troubleshooting Climate Control Panel Power and Ground Circuit Troubleshooting.
- If one or more LEDs or LCD segments do not blink, but at least one LED or LCD segment blinks, replace the climate control panel.
- If all LEDs and LCD segments blink, go to step 3.
3. Turn the ignition switch to LOCK (0), and then turn to ON (II).
4. At the rear climate control panel press and hold the OFF button. While holding the OFF button, press the REAR FAN V button five times within 10 seconds. Release the OFF button. All the LCD segments should blink three times.
- If none of the LCD segments blink, go to rear climate control panel power and ground circuit troubleshooting Rear Control Panel Power and Ground Circuit Troubleshooting.
- If one or more LCD segments do not blink, but at least one LCD segment does blink, replace the rear climate control panel.
- If all LCD segments blink, go to step 5.
5. Turn the ignition switch to LOCK (0), and then turn to ON (II).
6. At the climate control panel, press and hold the FAN � button and then the OFF button. While holding both buttons, the fan indicator will light the segment A. If there is any problem in the system, the fan indicator will light corresponding segment (B through E). Record any segments that light and go to step 7.
7. Turn the ignition switch to LOCK (0), and then turn to ON (II).
8. At the rear climate control panel, press and hold the REAR FAN � button and then the OFF button. While holding both buttons, the fan indicator will light the segment A. If there is any problem in the system, the fan indicator will light the corresponding segment (B through E).
- If no segment other than segment A light in either the climate control panel or the rear climate control panel, communication circuit is OK.
- If any segment other than segment A light, record the segments and then go to step 9.
9. Refer to the chart below and perform the appropriate diagnosis for the error indicated by the front and rear fan segments.
Displaying Sensor Inputs at the Front Climate Control Unit
The climate control unit has a mode that displays sensor inputs it receives. This mode shows you what the climate control unit is receiving from each of the sensors, one at a time, and it can help you determine if a sensor is faulty.
Check these items before using the sensor input display mode
1. Turn the ignition switch to ON (II), and check the recirculation door function; press the recirculation button to switch from FRESH to RECIRC. The air volume and sound should change slightly.
2. Set the temperature control knob to the desired test temperature. When selecting the test temperature, note these items:
- "Lo" temperature setting will default to MAX COOL, VENT, and RECIRC.
- "Hi" temperature setting will default to MAX HOT, FLOOR, and FRESH.
- 61 through 89 °F settings will use the automatic climate control logic.
3. Turn the ignition switch to LOCK (0).
To run the sensor input display mode, follow these steps
1. Turn the ignition switch to LOCK (0).
2. Press and hold both the AUTO and recirculation buttons, then start the engine.
3. After the engine starts, release the buttons. The display panel control unit will flash the sensor number and then the value for that sensor. Record the value displayed.
4. To advance to the next sensor, press the rear window defogger button.
NOTE:
- The sensor values will be displayed in degrees Celsius (°C) or an alphanumeric code. Use the chart to convert the value to degrees Fahrenheit (°F).
- If the sensor value displays "Er" this indicates there is an open or short in the circuit or sensor. Check for DTCs using the HDS, or refer to checking DTCs by DTC indication to check for DTCs.
- If necessary, compare the sensor input display to an alike, known-good vehicle under the same test conditions.
- If the sensor is out of the normal range, refer to the sensor test or substitute a known-good sensor, and recheck.
Celsius to Fahrenheit Conversion Table
Alphanumeric Conversion Table
5. To cancel the sensor input display mode, press the AUTO button or turn the ignition switch to LOCK (0).