DTC B1207 Smart ECU Stop

DESCRIPTION

This DTC is detected when communication between the certification ECU and gateway ECU stops for more than 10 seconds.

DTC No.	DTC Detection Condition	Trouble Area
B1207	Certification ECU communication stops	Certification ECU Wire harness

Dtc B1207 Smart Ecu Stop. MULTIPLEX COMMUNICATION. Lexus IS250 IS220d GSE20 ALE20

When "B of GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1206, repair the "+B or GND short malfunction of communication bus" DTCs first.

1.INSPECT FUSE (SECURITY)

Remove the SECURITY fuse from the main body ECU LH (cowl side J/B LH).

Measure the resistance of the fuse.

REPLACE FUSE

OK

2.CHECK WIRE HARNESS (CERTIFICATION ECU - BATTERY AND BODY GROUND)

Disconnect the P33 ECU connector.

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

Standard voltage:
Tester Connection Condition Specified Condition
+B1 (P33-1) - Body ground Always 10 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.CHECK RESISTANCE OF COMMUNICATION LINE

Disconnect the P33, RJ and M7 ECU connectors (for LHD).

Disconnect the P33, L17 and Q3 ECU connectors (for RHD).

Dtc B1207 Smart Ecu Stop. MULTIPLEX COMMUNICATION. Lexus IS250 IS220d GSE20 ALE20

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

Standard resistance:
Tester Connection Specified Condition
^*1MPX1 (P33-27) - MPX1 (RJ-21)
^*2MPX1 (P33-27) - MPX1 (L17-7) Below 1 Ω
^*1MPX2 (P33-28) - MPX2 (M7-8)
^*2MPX2 (P33-28) - MPX1 (Q3-15) Below 1 Ω

*1: LHD

*2: RHD

REPAIR OR REPLACE HARNESS OR CONNECTOR AND REPLACE CERTIFICATION ECU

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE CERTIFICATION ECU

Tester Connection	Condition	Specified Condition
+B1 (P33-1) - Body ground	Always	10 to 14 V

Tester Connection	Specified Condition
E (P33-17) - Body ground	Below 1 Ω