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 (MPX-B)
1. Remove the MPX-B fuse from the engine room J/B No. 1.
2. Measure the resistance of the fuse.
  Standard resistance:
  
  Below 1 Ω
NG: REPLACE FUSE

OK: Go to next step.

CHECK WIRE HARNESS (FRONT CONTROLLER - BATTERY AND BODY GROUND)

Disconnect the 2E and 2F ECU connectors.

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

Standard voltage

DTC DETECTION CONDITION AND TROUBLE AREA TABLE

Tester Connection	Condition	Specified Condition
2E-4 - Body ground	Always	10 to 14 V

Standard resistance

TESTER CONNECTION AND SPECIFIED CONDITION TABLE

Tester Connection	Specified Condition
2F-1 - Body ground	Below 1 ohms

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 1: Identifying Front Controller Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step.

CHECK RESISTANCE OF COMMUNICATION LINE

Disconnect the 2F, A30 and J55 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
2F-6 - MPX2 (A30-17)	Below 1 ohms
2F-5 - MPX2 (J55-24)	Below 1 ohms

Result

RESULT DESCRIPTION TABLE

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

B: REPAIR OR REPLACE HARNESS OR CONNECTOR AND REPLACE FRONT CONTROLLER

C: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 2: Identifying 2F, A30 & J55 ECU Connectors Terminals

A: REPLACE FRONT CONTROLLER