DTC B126A: Remote Engine Starter ECU Communication Stop [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - OPTION CONNECTOR)

Disconnect the H10 main body ECU (multiplex network body ECU) connector.
Disconnect the H151 option connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
H10-25 (BTX) - H151-7 (BTX)	Always	Below 1 Ω
H10-26 (BRX) - H151-3 (BRX)	Always	Below 1 Ω
H10-26 (BRX) - Body ground	Always	10 kΩ or higher
H151-3 (BRX) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step

REPLACE OPTION CONNECTOR
1. Replace the option connector.
NEXT: Go to next step
CHECK DTC OUTPUT
1. Clear the DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .
2. Recheck for DTCs.
  OK
  
  DTC B126A and B1269 are not output.
NG → See step 4

OK → END (OPTION CONNECTOR ECU WAS DEFECTIVE)
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to TERMINALS OF ECU [08/2013 - ]