DTC C1203: ECM Communication Circuit [10/2018 - ]: Procedure

1. Check that the proper hybrid vehicle control ECU and main body ECU (multiplex network body ECU) are installed.

   OK

   Proper ECUs are installed.

2. Check if the hybrid vehicle control ECU and main body ECU (multiplex network body ECU) were replaced before the DTC was recorded.

   OK

   ECUs were not replaced.

   Result

   Result	Proceed to
   OK	A
   NG (A proper hybrid vehicle control ECU is not installed and/or the hybrid vehicle control ECU 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

Result: 

B 

REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [10/2018 - 07/2022]  , or refer to  REMOVAL [07/2022 - ] 

Result: 

C 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [10/2018 - 07/2022]  , or refer to  REMOVAL [07/2022 - ] 

Result: 

A 

See step  2

1. Perform linear solenoid valve offset learning, ABS holding solenoid valve learning and system information memorization.

   Refer to INITIALIZATION [10/2018 - ]

   Chassis > ABS/VSC/TRAC > Utility 

   Tester Display
   ECB Utility

2. Perform yaw rate and acceleration sensor zero point calibration.

   Refer to CALIBRATION [10/2018 - ]

   Chassis > ABS/VSC/TRAC > Utility 

   Tester Display
   Test Mode

   HINT: 

   • After installing a new skid control ECU (brake booster with master cylinder assembly), before performing linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization, DTC C1203 will be output.
   • If linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization are not performed, DTC C1203 will be output after the data stored in the skid control ECU (brake booster with master cylinder assembly) is cleared by performing "Reset Memory" using Techstream.

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  3

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [10/2018 - ]

   Chassis > ABS/VSC/TRAC > Clear DTCs 

2. Turn the power switch off.
3. Turn the power switch on (IG).
4. Check if the same DTC is output.

   Refer to DTC CHECK / CLEAR [10/2018 - ]

   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 [10/2018 - 07/2022]  , or refer to  REMOVAL [07/2022 - ] 

Result: 

B 

END