DTC B1279: Rain Sensor Communication Stop: Procedure

WARNING: This page is about a different car, the 2010 Lexus GS 450h. However, it is still accessible from the selected car via links, so may be relevant.

CHECK RESISTANCE OF COMMUNICATION LINE

Fig 1: Identifying Communication Line Connectors

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Disconnect the W4 sensor connector.
Disconnect the W8 junction block connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

Tester Connection	Specified Condition
W4-1 (SIG) - W8-10 (IG2)	Below 1 Ω
W4-2 (MPX) - W8-9 (MPX1)	Below 1 Ω
W4-3 (ES) - W8-17 (GND2)	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK → REPLACE RAIN SENSOR