The C1203 code on Your Lexus means that You may have a damaged engine control module. The ECM harness hasnt been closed properly or it has short-circuited, or a case of bad wiring leading to reduced electrical power to the ECM. You will have to inspect the ECM to address these issues. You may have the ABS warning light turned on along with the engine light turned on as well. These lights could turn on as a result of the C1203 code. After the inspection, You can pinpoint the exact cause of Your troubles. If You cannot diagnose the problem Yourself, You will have to get the vehicle checked by a professional which would cost You around $75 to $150.
lucinda
March 4, 2024
Where can I check it at? Because my transmission people don't know the issues.?
Lucinda
January 22, 2024
Does the code c1203 does have to do anything with smog check?
Isabel R
July 30, 2020
The c1203 Lexus code IS for ECM Communication Circuit Malfunction.
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