A/C Signal Circuit Troubleshooting(Climate Control)

NOTE: 

• Do not use this troubleshooting procedure if any of the following items are operative with the A/C button and the blower control button 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. Evaporator outlet air temperature check:

  - 1. Start the engine.

  - 2. Set the A/C button and the blower control button to ON.

  - 3. Do the sensor input display mode - Refer to: How to Troubleshoot the Body ElectricalHow to Troubleshoot the Climate Control System  .

  Is Sensor #5 (evaporator outlet air temperature) above 3°C?

  YES 

  Go to step 3.

  NO 

  Go to step 10.

• 3. A/C pressure threshold check:

  - 1. Turn the vehicle to the OFF (LOCK) mode.

  - 2. Connect the HDS to the DLC.

  - 3. Turn the vehicle to the ON mode.

  - 4. 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 4.

  NO 

  Go to the A/C system test .

• 4. Climate control system check:

  - 1. Start the engine.

  - 2. Set the A/C button and the blower control button to ON.

  - 3. 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 5.

  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.

• 5. Determine possible failure area (ACS/TERMAL PRT line, others):

  - 1. Turn the vehicle to the OFF (LOCK) mode.

  - 2. Disconnect the following connector.

  Climate 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
  	Climate control unit 32P connector: disconnected
  Test point 1	Climate control unit 32P connector No. 24
  Test point 2	Body ground

  Is there battery voltage?

  YES 

  The ACS/TERMAL PRT wire is OK. Go to step 6.

  NO 

  Go to step 7.

• 6. Climate control unit check:

  - 1. Turn the vehicle to the OFF (LOCK) mode.

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

  - 3. Start the engine.

  - 4. Set the A/C button and the blower control button to ON.

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

  Test condition	Vehicle ON mode
  Test point 1	Climate control unit 32P connector No. 24
  Test point 2	Body ground

  Is there 0.2 V or less?

  YES 

  Replace the under-dash fuse/relay box .

  NO 

  Replace the climate control unit .

• 7. 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
  	Climate 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

  Courtesy of HONDA, U.S.A., INC.

  Is there battery voltage?

  YES 

  TERMAL PRT wire is OK. Go to step 8.

  NO 

  Go to step 9.

• 8. 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 climate control unit and the A/C compressor.

  NO 

  Replace the A/C compressor thermal protector .

• 9. MICU check:

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

  Test condition	Vehicle ON mode
  	Climate 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

  Courtesy of HONDA, U.S.A., INC.

  Is there battery voltage?

  YES 

  Repair an open in the wire between the A/C compressor and the under-dash fuse/relay box.

  NO 

  Replace the under-dash fuse/relay box .

• 10. Evaporator temperature sensor check:

  - 1. Turn the vehicle to the OFF (LOCK) mode.

  - 2. Disconnect the following connector.

  Climate control unit 32P connector

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

  Test condition	Vehicle OFF (LOCK) mode
  	Climate control unit 32P connector: disconnected
  Test point 1	Climate control unit 32P connector No. 18
  Test point 2	Climate control unit 32P connector No. 23

  Is the resistance less than 24 kΩ?

  YES 

  Replace the climate control unit .

  NO 

  Test the evaporator temperature sensor .