Inspection Procedure

WARNING: This page is about a different car, the 2007 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.

CHECK AIR CONDITIONING AMPLIFIER
1. Install the manifold gauge set.
2. Turn the ignition switch ON.
3. Check the voltage between terminals PSW (A47-8) and GND (A47-12) of the A/C amplifier connector when A/C gas pressure changes.
  OK: The voltage changes with gas pressure, as shown in the diagram below.
  
  HINT:
  
  However, if DTC 23 is displayed, check and replace the A/C amplifier.
  
  Fig 1: Checking Voltage Between Terminals PSW (A47-8) & GND (A47-12) Of A/C Amplifier Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Reference Table - High & Low Pressure Cut Side
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK: REPLACE AIR CONDITIONING AMPLIFIER

NG: GO TO NEXT STEP
CHECK PRESSURE SWITCH
1. Disconnect the A4 pressure switch connector.
2. Turn the ignition switch ON.
3. Check the continuity between terminals 1 and 2 of the pressure switch when A/C gas pressure changes.
  OK: The continuity changes with gas pressure as shown below.
  
  Fig 3: Identifying A4 Pressure Switch Connector Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 4: Reference Table - High & Low Pressure Cut Side
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE PRESSURE SWITCH

OK: GO TO NEXT STEP
CHECK WIRE HARNESS (PRESSURE SWITCH - AIR CONDITIONING AMPLIFIER)
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: REPLACE AIR CONDITIONING AMPLIFIER