Inspection Procedure

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.

INSPECT FUSE (H-LP LVL)
1. Remove the H-LP LVL fuse from the cowl side J/B LH.
2. Measure the resistance of the fuse.
  Standard resistance:
  
  Below 1 Ω
NG: REPLACE FUSE

OK: Go to next step.

CHECK WIRE HARNESS (AFS ECU - BATTERY AND BODY GROUND)

Disconnect the A27 ECU connector.
Turn the engine switch on (IG).

Measure the voltage and resistance of the wire harness side connector.

Standard voltage

TESTER CONNECTION AND SPECIFIED CONDITION TABLE

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

Standard resistance

TESTER CONNECTION AND SPECIFIED CONDITION TABLE

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

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 1: Identifying AFS ECU Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step.

CHECK RESISTANCE OF COMMUNICATION LINE

Disconnect the A27, J58 and J34 ECU connectors.

Measure the resistance between the specified terminals on the wire harness side connectors.

Standard resistance

TESTER CONNECTION AND SPECIFIED CONDITION TABLE

Tester Connection	Specified Condition
MPX1 (A27-5) - MPX- (J58-31)	Below 1 ohms
MPX2 (A27-6) - MPX+ (J34-6)	Below 1 ohms

Result

RESULT DESCRIPTION TABLE

Result	Proceed to
Both are OK	A
One is OK	B
Both are NG	C

B: REPLACE AFS ECU AND REPAIR OR REPLACE HARNESS OR CONNECTOR

C: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 2: Identifying A27, J58 & J34 ECU Connector Terminals

A: REPLACE AFS ECU