What does it mean?
OBD II fault code C1000 is a manufacturer-specific trouble code whose definition differs depending on the car maker. However, several brands are far more affected by this issue, and that’s what this article will focus on. First is Chrysler – which also owns Ram and Dodge – who defines the C1000 trouble code as an invalid signal between the master cylinder pressure applied and the Brake lamp switch output . This is detected by the ABS, with the issue being present for at least two minutes.
Furthermore, Mercedes-Benz has an almost identical description for this trouble code, whose vehicles commonly suffer from it. Lastly, certain cars made by Mitsubishi are known to have issues with recurring C1000 trouble codes, which is here defined as an Abnormality in a stoplight switch circuit . The C1000 trouble code in mentioned vehicles will be set when the ABS control module detects a signal from the brake light switch without corresponding brake activation.
Or, to put it simply, this happens when the car determines the brake switch is sending a false ON signal because it’s not braking. Apart from brake lights being constantly on, this also disables the ABS and cruise control if the vehicle has it. Still, remember some car makers might have a different explanation for the C1000 trouble code.