A/C Signal Circuit Troubleshooting(Heating/Air Conditioning)
NOTE:
- Do not use this troubleshooting procedure if any of the following items are operative with the A/C button and the blower control dial to ON: The A/C condenser fan, the radiator fan, or the A/C compressor. Refer to the symptom troubleshooting index - Refer to: Heating and A/C Systems Symptom Troubleshooting Index(Heating/Air Conditioning) Climate Control System Symptom Troubleshooting Index(Climate Control) .
- Do not use this troubleshooting procedure if the A/C system pressure is abnormal .
- Before doing symptom troubleshooting, check for PGM-FI DTCs - Refer to: How to Troubleshoot the Fuel and Emissions SystemsHow to Troubleshoot the CVT System(CVT System) .
- 1. Blower motor operation check:
- 1. Turn the vehicle to the ON mode.
- 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. A/C pressure threshold check:
- 1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Connect the HDS to the DLC.
- 3. Start the engine.
- 4. Set the A/C button and the blower control dial to ON.
- 5. Check the parameter(s) below with the HDS.
Signal Threshold Current conditions Values Unit Values Unit A/C PRESSURE SENSOR 196-2, 850 kPa 2.00-29.07 kgf/cm2 28.4-413.3 psi Do the current condition(s) match the threshold?
YES
Go to step 3.
NO
Go to the A/C system test .
- 3. HVAC control system check:
- 1. Check the parameter(s) below with the HDS.
Signal Threshold Current conditions Values Unit Values Unit A/C SWITCH ON A/C CLUTCH ON Do the current condition(s) match the threshold?
YES
Go to the A/C compressor clutch circuit troubleshooting .
NO
A/C SWITCH is OFF, go to step 4.
NO
A/C SWITCH is ON and A/C CLUTCH is OFF, update the PCM if it does not have the latest software, or substitute a known-good PCM , and recheck.
- 4. Determine possible failure area (ACS/TERMAL PRT line, others):
- 1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Disconnect the following connector.
HVAC control unit 32P connector - 3. Turn the vehicle to the ON mode.
- 4. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode HVAC control unit 32P connector: disconnected Test point 1 HVAC control unit 32P connector No. 25 Test point 2 Body ground Is there battery voltage?
YES
The ACS/TERMAL PRT wire is OK. Go to step 5.
NO
Go to step 6.
- 5. HVAC control unit check:
- 1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Reconnect the HVAC control unit 32P connector.
- 3. Start the engine.
- 4. Set the A/C button and the blower control dial to ON.
- 5. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode Test point 1 HVAC control unit 32P connector No. 25 Test point 2 Body ground Is there 0.2 V or less?
YES
Replace the under-dash fuse/relay box .
NO
Go to step 9.
- 6. Open wire check (TERMAL PRT line):
- 1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Disconnect the following connector.
A/C compressor clutch 3P connector - 3. Turn the vehicle to the ON mode.
- 4. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode HVAC control unit 32P connector: disconnected A/C compressor clutch 3P connector: disconnected Test point 1 A/C compressor clutch 3P connector No. 2 Test point 2 Body ground Is there battery voltage?
YES
TERMAL PRT wire is OK. Go to step 7.
NO
Go to step 8.
- 7. A/C compressor thermal protector check:
- 1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Test the A/C compressor thermal protector .
Is the A/C compressor thermal protector OK?
YES
Repair an open in the wire between the HVAC control unit and the A/C compressor.
NO
- 8. MICU check:
- 1. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode HVAC control unit 32P connector: disconnected A/C compressor clutch 3P connector: disconnected Test point 1 Under-dash fuse/relay box connector D (32P) No. 31 Test point 2 Body ground Is there battery voltage?
YES
Repair an open in the wire between the A/C compressor and the under-dash fuse/relay box.
NO
- 9. Evaporator temperature sensor check:
- 1. Turn the vehicle to the OFF (LOCK) mode.
- 2. Measure the resistance between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode HVAC control unit 32P connector: disconnected Test point 1 HVAC control unit 32P connector No. 19 Test point 2 HVAC control unit 32P connector No. 20 Is the resistance less than 24 kΩ?
YES
Replace the HVAC control unit .
NO
