AFS ECU Power Source Circuit: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / AFS / Data List.
5. Read the display on the Techstream.
   AFS (AFS ECU)
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   +B	Battery voltage value / 0 to 20 V	Engine switch off: Below 1 V Engine switch on (IG): 11 to 14 V	-

   OK

   Battery voltage is within the specified normal condition.

NG → See step   3 

OK → See step   2 

1. Disconnect the A27 AFS ECU connector.
   Fig 1: Identifying A27 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to AFS ECU)

2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A27-1 (E1) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (AFS ECU - BODY GROUND) 

OK: Go to next step 

1. Disconnect the A27 AFS ECU connector.
   Fig 2: Identifying A27 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to AFS ECU)

2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A27-2 (IG) - Body ground	Engine switch on (IG)	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (AFS ECU - BATTERY) 

OK → See step   5