How to Use the HVAC Control Unit Self-Diagnostic Function without the HDS
The HVAC control unit has a self-diagnostic function for heating, ventilation, and air conditioning system. To run the self-diagnostic function, do the following:
- Turn the ignition switch to LOCK (0) and then back to ON (II).
- Set the FAN speed to OFF with FAN ON/OFF button, the TEMPERATURE CONTROL dial on Max Cool, and select the VENT mode.
- Turn the ignition switch to LOCK (0) and then back to ON (II).
- Press and hold the RECIRCULATION CONTROL button, then within 10 seconds press and release the REAR WINDOW DEFOGGER/MIRROR DEFOGGER button five times. Release the RECIRCULATION CONTROL button; the recirculation indicator blinks two times, then the self-diagnostic begins.
NOTE:
- The self-diagnostic test could take up to two minutes to run.
- The blower motor should run at various speeds regardless of what the panel is displaying.
- If there is any problem in the system after the self-diagnostic function is finished, the recirculation indicator blinks Diagnostic Trouble Code (DTC) 1 through 9. In the case of multiple problems, the recirculation indicator blinks in order with the lowest number DTC repeatedly.
- If no DTCs are found, the indicator does not blink.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
| DTC (Recirculation Indicator Blinks) |
Detection Item |
| 1 |
A problem in the blower motor circuit (front) (see DTC B1241 OR DTC INDICATOR 1: A PROBLEM IN THE BLOWER MOTOR CIRCUIT (FRONT)
) |
| A problem in the rear blower motor circuit (see DTC B1223 OR DTC INDICATOR 1: A PROBLEM IN THE REAR BLOWER MOTOR CIRCUIT
) |
| 2 |
An open in the air mix control motor circuit (front) (see DTC B1233 OR DTC INDICATOR 2: AN OPEN IN THE AIR MIX CONTROL MOTOR CIRCUIT (FRONT)
) |
| A short in the air mix control motor circuit (front) (see DTC B1234 OR DTC INDICATOR 2: A SHORT IN THE AIR MIX CONTROL MOTOR CIRCUIT (FRONT)
) |
| A problem in the air mix control motor circuit, linkage, door, or motor circuit (front) (see DTC B1235 OR DTC INDICATOR 2: A PROBLEM IN THE AIR MIX CONTROL MOTOR CIRCUIT, LINKAGE, DOOR, OR MOTOR (FRONT)
) |
| 3 |
An open or short in the mode control motor circuit (front) (see DTC B1239 OR DTC INDICATOR 3: AN OPEN OR SHORT IN THE MODE CONTROL MOTOR CIRCUIT (FRONT)
) |
| A problem in the mode control motor circuit, linkage, door, or motor circuit (front) (see DTC B1240 OR DTC INDICATOR 3: A PROBLEM IN THE MODE CONTROL MOTOR CIRCUIT, LINKAGE, DOORS, OR MOTOR (FRONT)
) |
| 4 |
An open in the evaporator temperature sensor circuit (see DTC B1231 OR DTC INDICATOR 4: AN OPEN IN THE EVAPORATOR TEMPERATURE SENSOR CIRCUIT
) |
| A short in the evaporator temperature sensor circuit (see DTC B1232 OR DTC INDICATOR 4: A SHORT IN THE EVAPORATOR TEMPERATURE SENSOR CIRCUIT
) |
| 5 |
An open in the outside air temperature sensor circuit (see DTC B1227 OR DTC INDICATOR 5: AN OPEN IN THE OUTSIDE AIR TEMPERATURE SENSOR CIRCUIT
) |
| A short in the outside air temperature sensor circuit (see DTC B1228 OR DTC INDICATOR 5: A SHORT IN THE OUTSIDE AIR TEMPERATURE SENSOR CIRCUIT
) |
| 6 |
An open in the A/C pressure sensor circuit (see DTC B2979 OR DTC INDICATOR 6: AN OPEN IN THE A/C PRESSURE SENSOR CIRCUIT
) |
| A short in the A/C pressure sensor circuit (see DTC B2980 OR DTC INDICATOR 6: A SHORT IN THE A/C PRESSURE SENSOR CIRCUIT
) |
| 7 |
An open in the rear air mix control motor circuit (see DTC B1244 OR DTC INDICATOR 7: AN OPEN IN THE REAR AIR MIX CONTROL MOTOR CIRCUIT
) |
| A short in the rear air mix control motor circuit (see DTC B1245 OR DTC INDICATOR 7: A SHORT IN THE REAR AIR MIX CONTROL MOTOR CIRCUIT
) |
| A problem in the rear air mix control motor circuit, linkage, door, or motor (see DTC B1246 OR DTC INDICATOR 7: A PROBLEM IN THE REAR AIR MIX CONTROL MOTOR CIRCUIT, LINKAGE, DOOR, OR MOTOR
) |
| 8 |
An open or short in the recirculation control motor circuit (see DTC B1215 OR DTC INDICATOR 8: AN OPEN OR SHORT IN THE RECIRCULATION CONTROL MOTOR CIRCUIT
) |
| A problem in the recirculation control motor circuit, linkage, door, or motor (see DTC B2983 OR DTC INDICATOR 8: A PROBLEM IN THE RECIRCULATION CONTROL LINKAGE, DOOR, OR MOTOR CIRCUIT
) |
| 9 |
Engine coolant temperature (ECT) sensor signal error. Check for DTCs in the PGM-FI system and go to the indicated DTC'S TROUBLESHOOTING . If no DTCs are found, replace the HVAC control unit (see HVAC CONTROL UNIT REMOVAL/INSTALLATION
) |
Canceling the Self-Diagnostic Function
- Turn the ignition switch to LOCK (0), to cancel the self-diagnostic function. After completing the repair work, run the self-diagnostic function again to make sure that there are no other DTCs.