AFS ECU Power Source Circuit: Wiring Diagram

WARNING: This page is about a different car, the 2006 Lexus IS 350 and 2006 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Wiring Diagram - AFS ECU Power Source

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECT AFS ECU

Measure the voltage of the connector.

Standard voltage

SPECIFIED CONDITION AND TESTER CONNECTION

Tester Connection	Condition	Specified Condition
A27-1 (E1) - A27-2 (IG)	Engine switch off	Below 1 V
A27-1 (E1) - A27-2 (IG)	Engine switch on (IG)	10 to 14 V

Fig 2: Wiring Diagram - AFS ECU

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG : Go to step 2

OK : PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

CHECK WIRE HARNESS (AFS ECU - BODY GROUND)

Disconnect the A27 connector.
Measure the resistance of the wire harness side connector.

Standard resistance

SPECIFIED CONDITION AND TESTER CONNECTION

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

Fig 3: Identifying A27 Connector Terminal

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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

OK: Go To Next Step

INSPECT AFS ECU

Disconnect the A27 connector.
Measure the voltage of the connector.

Standard voltage

SPECIFIED CONDITION AND TESTER CONNECTION

Tester Connection	Condition	Specified Condition
A27-1 (IG) - A27-2 (E1)	Engine switch on (IG)	10 to 14 V

Fig 4: Identifying A27 Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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

OK : REPLACE AFS ECU