DTC C1203: ECM Communication Circuit [02/2019 - 12/2021]: Procedure

1. Check that the proper hybrid vehicle control ECU assembly, main body ECU (multiplex network body ECU) and yaw rate and acceleration sensor (airbag ECU assembly) are installed.

   OK

   Proper ECUs and sensor are installed.

2. Check if the hybrid vehicle control ECU assembly, main body ECU (multiplex network body ECU) and yaw rate and acceleration sensor (airbag ECU assembly) were replaced before the DTC was recorded.

   OK

   ECU or sensor was not replaced.

   Result

   Result	Proceed to
   OK	A
   NG (A proper hybrid vehicle control ECU assembly is not installed and/or the hybrid vehicle control ECU assembly was replaced.)	B
   NG (A proper main body ECU (multiplex network body ECU) is not installed and/or the main body ECU (multiplex network body ECU) was replaced.)	C
   NG (A proper yaw rate and acceleration sensor (airbag ECU assembly) is not installed and/or the yaw rate and acceleration sensor (airbag ECU assembly) was replaced.)	D

Result: 

B 

REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY. Refer to  REMOVAL [02/2019 - 10/2019]  , or refer to  REMOVAL [10/2019 - 08/2020]  , or refer to  REMOVAL [08/2020 - 12/2021] 

Result: 

C 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [02/2019 - 10/2019]  , or refer to  REMOVAL [10/2019 - 08/2020]  , or refer to  REMOVAL [08/2020 - 12/2021] 

Result: 

D 

REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [02/2019 - 10/2019]  , or refer to  REMOVAL [10/2019 - 08/2020]  , or refer to  REMOVAL [08/2020 - 12/2021] 

Result: 

A 

See step  2

1. Perform initialization and calibration of the linear solenoid valve.

   Refer to UTILITY [02/2019 - 12/2021]

   Chassis > ABS/VSC/TRAC > Utility 

   Tester Display
   ECB Utility

   HINT: 

   Before performing initialization and calibration of the linear solenoid valve, DTC C1203 will be output.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  3

1. Turn the ignition switch off.
2. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [02/2019 - 12/2021]

   Chassis > ABS/VSC/TRAC > Clear DTCs 

3. Turn the ignition switch off.
4. Turn the ignition switch to ON.
5. Check if the same DTC is output.

   Refer to DTC CHECK / CLEAR [02/2019 - 12/2021]

   Chassis > ABS/VSC/TRAC > Trouble Codes 

   Result

   Result	Proceed to
   DTC C1203 is output.	A
   DTC C1203 is not output.	B

Result: 

A 

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [02/2019 - 10/2019]  , or refer to  REMOVAL [10/2019 - 08/2020]  , or refer to  REMOVAL [08/2020 - 12/2021] 

Result: 

B 

END