Honda Civic. Manual — part 733

Fig. 6: Heater Control Panel - Circuit Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

DTC TROUBLESHOOTING

DTC INDICATOR 1: AN OPEN IN THE AIR MIX CONTROL MOTOR CIRCUIT

2008 Honda Civic EX

2006-08 HVAC Heating - Civic (All Except Hybrid)

1. Clear the DTC (see CLEAR THE DTCS ).
2. Turn the ignition switch to LOCK (0), and then ON (II).
3. Do the self-diagnostic with the heater control panel (see HOW TO USE THE

SELF-DIAGNOSTIC FUNCTION ).

4. Check for DTCs.

Is DTC 1 indicated?

YES -Go to step 5.

NO -Intermittent failure, check for loose wires or poor connections on the air
mix control motor circuit.

5. Turn the ignition switch to LOCK (0).
6. Test the air mix control motor (see AIR MIX CONTROL MOTOR TEST ).

Is the air mix control motor OK?

YES -Go to step 7.

NO -Replace the air mix control motor (see AIR MIX CONTROL MOTOR
TEST ).

7. Disconnect the air mix control motor 7P connector.
8. Disconnect the heater control panel 24P connector.
9. Check for continuity between the following terminals of the heater control

panel 24P connector and the air mix control motor 7P connector.

CONTINUITY CHECK INDEX

24P

7P

1

5

13

7

18

3

2008 Honda Civic EX

2006-08 HVAC Heating - Civic (All Except Hybrid)

Fig. 7: Check Continuity Between Heater Control Panel Connector & Air
Mix Control Motor Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Check for loose wires or poor connections at the heater control panel
24P connector and at the air mix control motor 7P connector. If the
connections are good, substitute a known-good heater control panel and
recheck. If the symptom/indication goes away, replace the original heater
control panel.

NO -Repair any open in the wires between the heater control panel and the air
mix control motor.

DTC INDICATOR 2: A SHORT IN THE AIR MIX CONTROL MOTOR CIRCUIT

1. Clear the DTC (see CLEAR THE DTCS ).
2. Turn the ignition switch to LOCK (0), and then ON (II).

2008 Honda Civic EX

2006-08 HVAC Heating - Civic (All Except Hybrid)

3. Do the self-diagnostic with the heater control panel (see HOW TO USE THE

SELF-DIAGNOSTIC FUNCTION ).

4. Check for DTCs.

Is DTC 2 indicated?

YES -Go to step 5.

NO -Intermittent failure.

5. Turn the ignition switch to LOCK (0).
6. Test the air mix control motor (see AIR MIX CONTROL MOTOR TEST ).

Is the air mix control motor OK?

YES -Go to step 7.

NO -Replace the air mix control motor (see AIR MIX CONTROL MOTOR
TEST ).

7. Disconnect the air mix control motor 7P connector.
8. Disconnect the heater control panel 24P connector.
9. Check for continuity between body ground and the heater control panel 24P

connector terminals No. 1, 13 and 18 individually.

2008 Honda Civic EX

2006-08 HVAC Heating - Civic (All Except Hybrid)