Air Conditioning Compressor Magnetic Clutch Circuit: Procedure

1. Connect Techstream to the DLC3.
2. Turn the ignition switch on (IG) and turn Techstream main switch on.
3. Turn the A/C switch on and off.
4. Select the item below in the Data List, and read the display on Techstream.
   DATA LIST / ENGINE:
   
   

   Tester Display	Measure Item/Range	Normal Condition	Diagnostic Note
   A/C Signal (A/C Signal)	A/C signal / ON or OFF	ON: A/C ON OFF: A/C OFF	-

   OK

   The display is as specified in the normal condition column.

NG → See step   8 

OK: Go to next step 

1. Remove the A/C NO. 2 fuse from the instrument panel junction block.
2. Measure the resistance of the fuse.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   A/C NO. 2	Always	Below 1 Ω

NG → REPLACE FUSE (A/C NO. 2) 

OK: Go to next step 

1. Remove the MG/CLT relay from the engine room relay block and junction block.
   Fig 1: Inspecting Magnet-Clutch Relay (MG/CLT)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   3 - 5	When battery voltage is not applied to terminals 1 and 2	10 kΩ or higher
   3 - 5	When battery voltage is applied to terminals 1 and 2	Below 1 Ω

NG → REPLACE MAGNET-CLUTCH RELAY (MG/CLT) 

OK: Go to next step 

1. Disconnect the connector from the air conditioning amplifier.
   Fig 2: Checking Harness And Connector (A/C Amplifier - Battery)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Condition	Specified Condition
   D37-20 (MGC) - Body ground	Ignition switch off	Below 1 V
   D37-20 (MGC) - Body ground	Ignition switch on (IG)	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Reconnect the connector to the air conditioning amplifier.
   Fig 3: Checking Air Conditioning Amplifier

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Condition	Specified Condition
   D37-20 (MGC) - Body ground	Ignition switch on (IG) Air conditioning switch: OFF	11 to 14 V
   D37-20 (MGC) - Body ground	Ignition switch on (IG) Air conditioning switch: ON	Below 1 V

NG → See step   9 

OK: Go to next step 

1. Disconnect the connector from the compressor and magnetic clutch.
   Fig 4: Measuring Resistance Of Compressor And Magnetic Clutch

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance of the connector.
3. When connector terminal 3 (MG+) is connected to the positive (+) battery terminal, and the body ground is connected to the negative (-) battery terminal, check that the following occurs: 1) the magnetic clutch's operating sound is emitted, and 2) the magnetic clutch's hub and rotor lock.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   B66-3 (MG+) - Body ground	Always	Below 1 Ω

NG → See step   10 

OK: Go to next step 

1. Remove the MG/CLT relay from the engine room relay block and junction block.
   Fig 5: Identifying MG/CLT Relay From The Engine Room Relay Block

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Condition	Specified Condition
   Relay block MG/CLT relay terminal 5 - Body ground	Ignition switch on (IG)	11 to 14 V
   Relay block MG/CLT relay terminal 1 - Body ground	Ignition switch on (IG)	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM R/B AND J/B - BATTERY) 

OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM R/B AND J/B - A/C COMPRESSOR)