A/C Signal Circuit Troubleshooting

A/C compressor clutch condition check

-1. Start the engine, and let it idle.

- 2. Turn the blower switch on.

- 3. Turn the A/C switch on.

- 4. Check the parameter(s) below with the HDS.

Signal	Threshold		Current conditions
Signal	Values	Unit	Values	Unit
A/C CLUTCH	ON

Do the current condition(s) match the threshold?

YES

Go to step 2.

Do the A/C system test - Refer to: A/C System Test, or A/C System Test, or A/C System Test (2017 2018 2019 2020) .

A/C system check
-1. Check the A/C system.

Does the A/C system operate?

YES

The A/C system circuit is OK.

NO

Go to step 3.
A/C compressor clutch circuit check
-1. Turn the vehicle to the OFF (LOCK) mode.

- 2. Turn the vehicle to the ON mode.

- 3. Activate the A/C CLUTCH in the INSPECTION MENU with the HDS.

A/C CLUTCH

Is there a clicking noise from the A/C compressor clutch?

YES

The A/C compressor clutch circuit is OK. Do the A/C system test - Refer to: A/C System Test, or A/C System Test, or A/C System Test (2017 2018 2019 2020) .

NO

Go to step 4.

Open wire check (ACCL line)

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

- 2. Jump the SCS line with the HDS.

- 3. Disconnect the following connector.

PCM connector A (51P) - Refer to: How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the A/T System (2014 2015)

- 4. Turn the vehicle to the ON mode.

- 5. Connect terminals A and B with a jumper wire.

Terminal A	PCM connector A (51P) No. 23 (PUR)
Terminal B	Body ground

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

Is there a clicking noise from the A/C compressor clutch?

YES

The ACCL wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) , then recheck. If the symptom/indication goes away and the PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the PCM was substituted, replace the original PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .

Check for poor connections or loose terminals at the A/C compressor clutch relay and the PCM. If the connections and terminals are OK, check the A/C compressor clutch relay. If needed, repair open in the ACCL wire between the PCM (A23) and the A/C compressor clutch relay, or other parts in the A/C systems.