What causes C1203 on a Toyota?

Open or short on the CAN bus Faulty skid control ECU Faulty engine control module Corroded connector Damaged body harness

How do I fix C1203 on a Toyota?

Confirm the code with a scan tool Inspect and reseat the ECU connectors Test the CAN bus for opens and shorts Check ECU power and ground Replace an ECU only after tests fail

C1203 ECM communication circuit malfunction in the skid control system

Q: What does C1203 mean on a Toyota?

C1203. ECM communication circuit malfunction in the skid control system. The skid control ECU cannot exchange data with the engine control module. Applies to Toyota, Lexus and Scion models that use this code.

Category: Chassis
Severity: ABS Light
Applies to: Toyota, Lexus and Scion models that use this code

What does C1203 mean on a Toyota?

C1203. ECM communication circuit malfunction in the skid control system. The skid control ECU cannot exchange data with the engine control module. This Toyota-enhanced code applies to Toyota, Lexus and Scion models that use this code.

Common causes of C1203

Open or short on the CAN bus
Faulty skid control ECU
Faulty engine control module
Corroded connector
Damaged body harness

How to fix C1203

Confirm the code with a scan tool
Inspect and reseat the ECU connectors
Test the CAN bus for opens and shorts
Check ECU power and ground
Replace an ECU only after tests fail