A/C Signal Circuit Troubleshooting (Climate Control System)
A/C Signal Circuit Troubleshooting
NOTE:
- Do not use this troubleshooting procedure if any of the following items are operative: A/C condenser fan, radiator fan, A/C compressor. Refer to the symptom troubleshooting index.
- Do not use this troubleshooting procedure if the A/C system pressure is abnormal Description and Operation.
- Before doing symptom troubleshooting, check for powertrain DTCs Initial Inspection and Diagnostic Overview.
1. Turn the ignition switch to ON (II).
2. Check that the blower motor operates at all speeds.
Does the blower motor operate at all speeds?
YES -
Go to step 3.
NO -
Repair the problem in the blower motor circuit.�
3. Start the engine.
4. Turn on the A/C.
5. Do the sensor input display mode Initial Inspection and Diagnostic Overview.
Is Sensor #5 (evaporative outlet air temperature) above 3°C?.
YES -
Go to step 6.
NO -
Go to step 16.
6. Turn the ignition switch to LOCK (0).
7. Connect the HDS to the DLC.
8. Using the HDS, confirm the following values in the PGM-FI Data List at idle.
Are all the values within specifications?
YES -
Go to step 9.
NO -
Troubleshoot the value that is not within the specifications.�
9. Disconnect climate control unit connector A (32P).
10. Turn the ignition switch to ON (II).
11. Measure the voltage between climate control unit connector A (32P) terminal No. 6 and body ground.
Is there battery voltage?
YES -
Go to step 12.
NO -
Repair an open in the wire between the climate control unit and MICU.�
12. Turn the ignition switch to LOCK (0).
13. Reconnect climate control unit connector A (32P).
14. Set the A/C button and fan control switch ON, then turn the ignition switch to ON (II).
15. Measure the voltage between climate control unit connector A (32P) terminal No. 6 and body ground.
Is there 0.5 V or less?
YES -
Replace the MICU Under-dash Fuse/Relay Box Removal/Installation.�
NO -
Check for loose wires or poor connections at climate control unit connector A (32P). If the connections are 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.�
16. Turn the ignition switch to LOCK (0).
17. Disconnect climate control unit connector A (32P).
18. Measure the evaporator temperature sensor resistance between the climate control unit connector A (32P) terminals No. 8 and No. 19.
Is the resistance less than 24 kOhms?
YES -
Check for lose wires or poor connections at the climate control unit connector A (32P). If the connections are good, substitute a known-good climate control unit and recheck. If the symptom goes away, replace the original climate control unit Climate Control Unit Removal/Installation.�
NO -
Test the evaporator temperature sensor Evaporator Temperature Sensor Test.�