A/C Pressure Switch Circuit Troubleshooting.

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Honda Odyssey, 2003 Honda Odyssey, 2002 Honda Odyssey, 2001 Honda Odyssey, and 2000 Honda Odyssey. 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; condenser fan radiator fan A/C compressor or if the heater is inoperative. Refer to the symptom troubleshooting index.
Before performing symptom troubleshooting check for powertrain DTCs (see GENERAL TROUBLESHOOTING INFORMATION ).

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 battery voltage?
1. YES - Go to step 4.
2. NO - Repair open in the wire between the A/C diode A, the PCM 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 6.
2. NO - Go to step 13 .
Reconnect the A/C pressure switch 4P connector.
Does the vehicle have a Navigation System?
1. YES - Go to step 10 .
2. NO - Go to step 7.
Disconnect climate control unit connector B (20P).
Turn the ignition switch ON (II).
Measure the voltage between the No. 2 terminal of climate control unit connector B (20P) and body ground.

Fig 3: Measuring Voltage Between No. 2 Terminal Of Climate Control Unit Connector B (20P) & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES -Check for loose wires or poor connections at climate control unit connector B (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 open in the wire between the climate control unit and the A/C pressure switch.
Disconnect climate control unit connector B (26P).
Turn the ignition switch ON (II).
Measure the voltage between the No. 4 terminal of climate control unit connector B (26P) and body ground.

Fig 4: Measuring Voltage Between No. 4 Terminal Of Climate Control Unit Connector B (26P) & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?
1. YES - Check for loose wires or poor connections at climate control unit connector B (26P) 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 open in the wire between the climate control unit and the A/C pressure switch.
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.