Inspection Procedure

HINT:

When "+B or GND short malfunction of communication bus" DTCs (B1266 and B1267) are detected at the same time as "communication stop" DTC B1279, repair the "+B or GND short malfunction of communication bus" DTCs first.

INSPECT FUSE (ECU-IG NO. 1)
1. Remove the ECU-IG No. 1 fuse from the fusible link block.
2. Measure the resistance of the fuse.
  Standard resistance:
  
  Below 1 Ω
NG: REPLACE FUSE

OK: Go to next step.

CHECK WIRE HARNESS (RAIN SENSOR - BATTERY AND BODY GROUND)

Disconnect the R7 sensor connector.

Measure the voltage of the wire harness side connector.

Standard voltage

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
R7-1 (SIG) - Body ground	Ignition switch ON	10 to 14 V

Measure the resistance of the wire harness side connector.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Specified Condition
R7-3 (ES) - Body ground	Below 1 Ω

Fig 1: Identifying Terminals Of R7 Sensor Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step.

CHECK RESISTANCE OF COMMUNICATION LINE

Disconnect the G3 and C8 ECU connectors (with LEXUS navigation system).
Disconnect the C4 and C8 ECU connectors (without LEXUS navigation system).

Fig 2: Identifying Terminals Of G3, C4 And C8 ECU Connectors
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Measure the resistance of the wire harness side connectors.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection

Specified Condition

R7-2 (MPX) - G3-13 (MPI2) (⁽¹⁾)

Below 1 Ω

R7-2 (MPX) - C4-12 (MPX-) (⁽²⁾)

Below 1 Ω

R7-2 (MPX) - C8-5 (MPX-)

Below 1 Ω

⁽¹⁾	with LEXUS Navigation System

⁽²⁾	without LEXUS Navigation System

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE RAIN SENSOR