DTC C1242: Open Circuit in IG1/IG2 Power Source Circuit [08/2015 - ]: Procedure

1. Disconnect the A7 skid control ECU connector.
2. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A7-1 (IG2) - Body ground	Ignition switch ON	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Skid Control ECU)

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  2

See step  2[08/2015 - 08/2019], or refer to PROCEDURE - Step 2 [08/2019 - ]

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Clear the DTCs (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] , or refer to DTC CHECK / CLEAR [08/2019 - ] ).
2. Turn the ignition switch off.
3. Check if the same DTC is output (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] , or refer to DTC CHECK / CLEAR [08/2019 - ] ).

   HINT: 

   Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

   RESULT
   
   

   Result	Proceed to
   DTC is output	A
   DTC is not output	B

Result: 

A 

REPLACE MASTER CYLINDER SOLENOID 

(Refer to DISASSEMBLY [08/2015 - ] )

Result: 

B 

USE SIMULATION METHOD TO CHECK 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - 08/2019] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] )