DTC C1203: ECM Communication Circuit Malfunction [12/2017 - 09/2018]: Procedure

1. Check that the proper ECM is installed.

   OK

   Proper ECM is installed.

2. Check if the ECM was replaced before the DTC was stored.

   OK

   ECM was not replaced

   Result

   Result	Proceed to
   OK	A
   NG (A proper ECM is not installed and/or the ECM was replaced.)	B

Result: 

B 

REPLACE ECM. Refer to  REMOVAL [12/2017 - 09/2018] 

Result: 

A 

See step  2

1. For vehicles with the VGRS system, check that the part number of the installed VGRS ECU (front steering control ECU) is correct. For vehicles without the VGRS system, make sure that a VGRS ECU (front steering control ECU) is not installed.

   OK

   The presence or absence of the VGRS ECU (front steering control ECU) appropriately matches the specifications of the vehicle.

2. Check if the VGRS ECU (front steering control ECU) had been replaced before the DTC was stored.

   OK

   ECU had not been replaced.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE FRONT STEERING CONTROL ECU. Refer to  REMOVAL [12/2017 - 09/2018] 

Result: 

OK 

See step  3

1. Check that the installed steering sensor matches the vehicle specification.

   OK

   The steering sensor installation matches the vehicle specification.

2. Check if the steering sensor had been replaced before the DTC was stored.

   OK

   Sensor had not been replaced.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE STEERING SENSOR. Refer to  REMOVAL [12/2017 - 09/2018] 

Result: 

OK 

See step  4

1. Check that the proper brake actuator assembly is installed.

   OK

   Proper brake actuator assembly is installed.

2. Check if the brake actuator assembly was replaced before the DTC was recorded.

   OK

   The brake actuator assembly was not replaced.

   Result

   Result	Proceed to
   OK	A
   NG (A proper brake actuator assembly is not installed.)	B
   NG (The brake actuator assembly was replaced.)	C

Result: 

B 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018] 

Result: 

C 

See step  6

Result: 

A 

See step  5

1. Clear the DTC.

   Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

   Chassis > ABS/VSC/TRAC > Clear DTCs 

2. Check if the same DTC is recorded.

   Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

   Chassis > ABS/VSC/TRAC > Trouble Codes 

   Result

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

Result: 

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 09/2018] 

Result: 

B 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018] 

1. Perform initialization and calibration.

   Refer to CALIBRATION [12/2017 - 09/2018]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  7

1. Clear the DTC.

   Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

   Chassis > ABS/VSC/TRAC > Clear DTCs 

2. Check if the same DTC is recorded.

   Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

   Chassis > ABS/VSC/TRAC > Trouble Codes 

   Result

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

Result: 

A 

END 

Result: 

B 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018]