A/C Pressure Switch 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 .
Before performing symptom troubleshooting, check for power train DTCs (see GENERAL TROUBLESHOOTING INFORMATION ).

Check for body DTCs using B-CAN system diagnosis test mode A troubleshooting (see TROUBLESHOOTING -- B-CAN SYSTEM DIAGNOSIS TEST MODE A ).
Are there any DTCs indicated?
1. YES - Do the appropriate troubleshooting for the DTC indicated.
2. NO - Go to step 2.
Disconnect the A/C pressure switch 4P connector.
Turn the ignition switch ON (II).
Measure the voltage between the No. 1 terminal of the A/C pressure switch 4P connector and body ground.

Fig 1: Measuring Voltage Between No. 1 Terminal Of A/C Pressure Switch 4P Connector & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there 5 V or more?
1. YES - Go to step 5.
2. NO - Repair open in the wire between the relay control module and the A/C pressure switch.
Turn the ignition switch OFF.
Check for continuity between the No. 1 and No. 4 terminals of the A/C pressure switch.

Fig 2: Checking Continuity Between No. 1 & No. 4 Terminals Of A/C Pressure Switch
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 7.
2. NO - Go to step 16
Reconnect the A/C pressure switch 4P connector.
Disconnect climate control unit connector A (20P).
Turn the ignition switch ON (II).
Measure the voltage between the No. 14 terminal of climate control unit connector A (20P) and body ground.

Fig 3: Measuring Voltage Between No. 14 Terminal Of Climate Control Unit Connector A (20P) & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there 5 V or more?
1. YES - Go to step 11.
2. NO - Repair open in the wire between the climate control unit and the A/C pressure switch.
Turn the ignition switch OFF.
Measure the evaporator sensor resistance between the No. 5 and No. 18 terminals of climate control unit connector A (20P).
CLIMATE CONTROL UNIT CONNECTOR A (20P)

Fig 4: Measuring Evaporator Sensor Resistance Between No. 5 & No. 18 Terminals Of Climate Control Unit Connector A (20P)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is the resistance less than 24 kΩ?
1. YES - Go to step 13.
2. NO - Repair cause of high resistance in the evaporator temperature circuit.
Reconnect climate control unit connector A (20P).
Turn the ignition switch ON (II).
Check that blower motor operates at all speeds.
Does the blower motor operate at all speeds?
1. YES - Check for loose wires or poor connections at climate control unit connector A (20P) and at the A/C pressure switch 4P connector. 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.
2. NO - Repair the problem in the blower motor circuit.
Check for proper A/C system pressure.
Is the pressure within specifications?
1. YES - Replace the A/C pressure switch.
2. NO - Repair the A/C pressure problem.