Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

When "+B or GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1279, repair the "+B or GND short malfunction of communication bus" DTCs first.

INSPECT FUSES (ALT, INP-J/B, ECU-IG NO. 1)
1. Remove the ALT and INP-J/B (*1) fuses from the fusible link block.
  HINT:
  
  *1: without Air Suspension System
2. Remove the ECU-IG No. 1 fuse from the instrument panel J/B.
3. Measure the resistance of the fuses.
  Standard resistance:
  
  Below 1 Ω
NG: REPLACE FUSE

OK: Go to Next Step

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

Fig 1: Identifying R7 Connectors Terminal

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Disconnect the R7 connector.

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

Standard voltage

VOLTAGE SPECIFICATION TABLE

Tester Connection	Condition	Specified Condition
SIG (R7-1) - Body ground	Turn the ignition switch to the ON position	10 to 14 V

Standard resistance

RESISTANCE SPECIFICATION TABLE

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

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to Next Step

CHECK RESISTANCE OF COMMUNICATION LINE

Fig 2: Identifying R7 & C8 ECU Connector Terminals

Disconnect the R7 and C8 ECU connectors.

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

Standard resistance

RESISTANCE SPECIFICATION TABLE

Tester Connection	Specified Condition
MPX (R7-2) - C8-5	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE RAIN SENSOR