ECM Communication Circuit Malfunction
Table of contents
C1203 TOYOTA Possible Causes
- Faulty Engine Control Module (ECM)
- Engine Control Module harness is open or shorted
- Engine Control Module circuit poor electrical connection
How do I fix code C1203 TOYOTA?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- DTC C1203/95 is output when an incorrect ECU is installed. If initialization is performed and learning occurs with an incorrect ECU installed, operations and functions will differ from that stored when the vehicle was shipped from the factory. Therefore, make sure that learning occurs properly.
Cost of diagnosing the C1203 TOYOTA code
The cost of diagnosing the C1203 TOYOTA code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Anti-Lock Brake System (ABS) Warning Light ON
- Engine Light ON (or Service Engine Soon Warning Light)
C1203 TOYOTA Description
The circuit is used to send TRAC and VSC information from the skid control ECU to the Engine Control Module (ECM), and hybrid control system information from the Engine Control Module to the skid control ECU via the CAN communication system.
Identification information sent from other ECUs is stored when shipped from the factory and used as default values.