A/C Pressure Switch Circuit Troubleshooting

WARNING: This page is about a different car, the 2013 Honda Fit, 2012 Honda Fit, 2011 Honda Fit, 2010 Honda Fit, and 2009 Honda Fit. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Do not use this troubleshooting procedure if any of the following items are operative; the condenser fan, the radiator fan, the A/C compressor, or if the heater is inoperative. Refer to SYMPTOM TROUBLESHOOTING INDEX .
Check the A/C high-side pressure.
Before doing any symptom troubleshooting, check for powertrain DTCs (see GENERAL TROUBLESHOOTING INFORMATION ).

Disconnect the A/C pressure switch 2P connector.
Turn the ignition switch to ON (II).
Measure the voltage between A/C pressure switch 2P connector terminal No. 2 and body ground.
Is there battery voltage?

YES - Go to step 4.

NO - Go to step 20.

Fig 1: Measuring Voltage Between A/C Pressure Switch 2P Connector Terminal No. 2 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to LOCK (0).
Check for continuity between A/C pressure switch terminals No. 1 and No. 2.
Is there continuity?

YES - Go to step 6.

NO - Replace the A/C pressure switch.

Fig 2: Checking Continuity Between A/C Pressure Switch Terminals No. 1 & No. 2
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Reconnect the A/C pressure switch 2P connector.
Disconnect the A/C switch 5P connector.
Turn the ignition switch to ON (II).
Measure the voltage between A/C switch 5P connector terminal No. 2 and body ground.
Is there battery voltage?

YES - Go to step 10.

NO - Repair open in the wire between the A/C pressure switch and the A/C switch.

Fig 3: Measuring Voltage Between A/C Switch 5P Connector Terminal No. 2 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to LOCK (0).
Test the A/C switch (see A/C SWITCH REPLACEMENT ).
Is the A/C switch OK?

YES - Go to step 12.

NO - Replace the A/C switch (see A/C SWITCH REPLACEMENT ).
Disconnect the heater fan switch 8P connector.
Check for continuity between A/C switch 5P connector terminal No. 1 and heater fan switch 8P connector terminal No. 6.
Is there continuity?

YES - Go to step 14.

NO - Repair open in the wire between the A/C switch and the heater fan switch.

Fig 4: Checking Continuity Between A/C Switch 5P Connector Terminal No. 1 & Heater Fan Switch 8P Connector Terminal No. 6
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Test the heater fan switch (see HEATER FAN SWITCH TEST ).
Is the heater fan switch OK?

YES - Go to step 15.

NO - Replace the heater fan switch (see HEATER CONTROL PANEL DISASSEMBLY AND REASSEMBLY ).
Remove the evaporator temperature sensor (see EVAPORATOR CORE REPLACEMENT ) and test it (see EVAPORATOR CORE REPLACEMENT ).
Is the evaporator temperature sensor OK?

YES - Go to step 16.

NO - Replace the evaporator temperature sensor (see EVAPORATOR CORE REPLACEMENT ).
Jump the SCS line with the HDS.
NOTE: This step must be done to protect engine/powertrain control module (ECM/PCM) from damage.
Disconnect ECM/PCM connector A (49P).
Check for continuity between the following terminals of ECM/PCM connector A (49P) and the evaporator temperature sensor 2P connector.
49P: 2P:

No. 10 No. 2

No. 38 No. 1

Fig 5: Checking Continuity Between Terminals Of ECM/PCM Connector A (49P) And Evaporator Temperature Sensor 2P Connector
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES - Go to step 19.

NO - Repair open in the wire(s) between the ECM/PCM and the evaporator temperature sensor.
Check for continuity between ECM/PCM connector A (49P) terminal No. 38 and body ground.
Is there continuity?

YES - Repair short to body ground in the wire between the ECM/PCM and the evaporator temperature sensor.

NO - Check for loose wires or poor connections at ECM/PCM connector A (49P), the evaporator temperature sensor 2P connector, the A/C pressure switch 2P connector, the A/C switch 5P connector, and at the heater fan switch 8P connector. If the connections are good, substitute a known-good ECM/PCM, and recheck. If the symptom/indication goes away, replace the original ECM/PCM.

Fig 6: Checking Continuity Between ECM/PCM Connector A (49P) Terminal No. 38 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to LOCK (0).
Reconnect the A/C pressure switch 2P connector.
Disconnect the A/C compressor clutch 3P connector.
Turn the ignition switch to ON (II).
Measure the voltage between A/C compressor clutch 3P connector terminal No. 3 and body ground.
Is there battery voltage?

YES - Go to step 25.

NO - Go to step 27.

Fig 7: Measuring Voltage Between A/C Compressor Clutch 3P Connector Terminal No. 3 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Turn the ignition switch to LOCK (0).
Test the A/C compressor thermal protector (see A/C COMPRESSOR CLUTCH CHECK ).
Is the A/C compressor thermal protector OK?

YES - Repair open in the wire between the A/C compressor clutch and the A/C pressure switch.

NO - Replace the A/C compressor thermal protector (see A/C COMPRESSOR THERMAL PROTECTOR REPLACEMENT ).
Turn the ignition switch to LOCK (0).
Reconnect the A/C pressure switch 3P connector.
Make sure the A/C switch is OFF.
Turn the ignition switch to ON (II).
Measure the voltage between under-dash fuse/relay box connector A (36P) terminal No. 21 and body ground with the under-dash fuse/relay box connectors connected.
Is there battery voltage?

YES - Repair open in the wire between the A/C compressor and the MICU.

NO - Check for loose wires or poor connections at the under-dash fuse/relay box. If the connections are OK, substitute a known-good MICU and recheck. If the symptom goes away, replace the original MICU.

Fig 8: Measuring Voltage Between Under-Dash Fuse/Relay Box Connector A (36P) Terminal No. 21 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.