A/C Signal Circuit Troubleshooting (With Climate Control)

HVAC

A/C Signal Circuit Troubleshooting - Climate Control

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.
* Before doing symptom troubleshooting, check for PGM-FI DTCs Initial Inspection and Diagnostic Overview.

1. Blower motor operation check:

Blower motor operation check
-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 2.
-NO- Repair the problem in the blower motor circuit.

2. Climate control system check 1:

Climate control system check 1
-1. Start the engine.

-2. Turn on the A/C.

-3. Do the sensor input display mode.

Is Sensor #5 (evaporative outlet air temperature) above 3°C?
-YES- Go to step 3.
-NO- Go to step 6.

3. Climate control system check 2:

Climate control system check 2
-1. Turn the ignition switch to LOCK (0).

-2. Connect the HDS to the DLC.

-3. Start the engine.

-4. Turn on the A/C.

-5. 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 4.
-NO- Troubleshoot the value that is not within the specifications.

4. Open wire check (ACS line):

Open wire check (ACS line)
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.





-3. Turn the ignition switch to ON (II).

-4. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- The ACS wire is OK. Go to step 5.
-NO- Repair an open in the wire between the climate control unit and the MICU.

5. Climate control unit check:

Climate control unit check
-1. Turn the ignition switch to LOCK (0).

-2. Reconnect the climate control unit 32P connector.

-3. Turn the ignition switch to ON (II).

-4. Turn on the A/C.

-5. Measure the voltage between test points 1 and 2.









Is there 0.2 V or less?
-YES- Replace the MICU Service and Repair.
-NO- Replace the climate control unit; with navigation Climate Control Unit Removal And Installation (With Navigation), without navigation Climate Control Unit Removal And Installation (Without Navigation).

6. Evaporator temperature sensor check:

Evaporator temperature sensor check
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.





-3. Measure the resistance between test points 1 and 2.









Is the resistance less than 24 kOhms?
-YES- Replace the climate control unit; with navigation Climate Control Unit Removal And Installation (With Navigation), without navigation Climate Control Unit Removal And Installation (Without Navigation).
-NO- Test the evaporator temperature sensor Service and Repair.