Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.

HINT

If "+B of GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1278, repair the "+B or GND short malfunction of communication bus" DTCs first (See DTC B1214 SHORT TO B+ IN DOOR SYSTEM COMMUNICATION BUS MALFUNCTION; DTC B1215 SHORT TO GND IN DOOR SYSTEM COMMUNICATION BUS MALFUNCTION )

INSPECT FUSE (ECU-IG RH, MPX-B)

Remove the ECU-IG RH fuse from the main body ECU RH (cowl side junction block RH)
Remove the MPX-B fuse from the engine room relay block No. 1

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

Standard Resistance

RESISTANCE REFERENCE

Tester Connection	Condition	Specified Condition
ECU-IG RH fuse	Always	Below 1 Ω
MPX-B fuse	Always	Below 1 Ω

NG: REPLACE FUSE (ECU-IG RH, MPX-B)

OK: Go to Next Step

CHECK HARNESS AND CONNECTOR (WINDSHIELD WIPER SWITCH - BATTERY AND BODY GROUND)

Disconnect the J26 connector.

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

Standard Voltage

VOLTAGE SPECIFICATION

Tester Connection	Condition	Specified Condition
J26-1 (B) - Body ground	Always	11 to 14 V
J26-2 (IG) - Body ground	Engine switch on (IG)	11 to 14 V

Standard Resistance

RESISTANCE REFERENCE

Tester Connection	Condition	Specified Condition
J26-5 (E) - Body ground	Always	Below 1 Ω

Fig 1: Identifying J26 Connector Terminal

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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (WINDSHIELD WIPER SWITCH - BATTERY AND BODY GROUND)

OK: Go to Next Step

CHECK HARNESS AND CONNECTOR (COMMUNICATION LINE)

Disconnect the J26, J76 and J55 connectors

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

Standard Resistance

RESISTANCE REFERENCE

Tester Connection	Condition	Specified Condition
J26-6 (MPX1) - J76-12 (MPD2)	Always	Below 1 Ω
J26-7 (MPX2) - J55-7 (MPX1)	Always	Below 1 Ω

Fig 2: Identifying J26, J76 And J55 Connector Terminal

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE WINDSHIELD WIPER SWITCH (See REMOVAL )