Inspection Procedure

WARNING: This page is about a different car, the 2007 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 B1277, repair the "+B or GND short malfunction of communication bus" DTCs first.

INSPECT FUSE (ECU-B)
1. Remove the ECU-B 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 (CENTER CLUSTER INTEGRATION PANEL - BATTERY AND BODY GROUND)

Fig 1: Identifying C4 Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Disconnect the C4 switch connector.

Check the voltage between the wire harness side connector and the body ground.

Standard voltage

VOLTAGE SPECIFICATION TABLE

Tester Connection	Condition	Specified Condition
C4-1 (+B) - Body ground	Always	10 to 14 V

Standard resistance

RESISTANCE SPECIFICATION TABLE

Tester Connection	Specified Condition
GND (C4-7) - 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 C4, C8 & G3 Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Disconnect the C4, C8 and G3 connectors.

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

Standard resistance

RESISTANCE SPECIFICATION TABLE

Tester Connection	Specified Condition
MPX+ (C4-5) - C8-5	Below 1 Ω
MPX- (C4-12) - MPI2 (G3-13)	Below 1 Ω

Result

RESULT TABLE

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

B: REPLACE CENTER CLUSTER INTEGRATION PANEL AND WIRE HARNESS OR CONNECTOR

C: REPAIR OR REPLACE HARNESS OR CONNECTOR

A: REPLACE CENTER CLUSTER INTEGRATION PANEL