Code Definition

C1209 — ABS Inlet Valve Coil Rear Circuit Short To Ground

System: Chassis  |  Type: Manufacturer-Specific  |  Make: Generic

About C1209

C1209 is a manufacturer-specific chassis diagnostic trouble code. It belongs to the C-prefix family of codes, which covers chassis, braking, steering, suspension, or stability-control faults.

When C1209 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit.

Scanning & clearing: Chassis (C) codes are stored in the ABS, traction control, or stability-control modules. An enhanced or OEM-level scan tool is usually required to read and clear them.

C1209 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The ABS hydraulic control unit (HCU) contains inlet and outlet solenoid valves for each controlled wheel circuit. The rear inlet (isolation) valve closes to hold or isolate brake pressure in the rear circuit during an ABS event. DTC C1209 is set when the ABS module detects that the rear inlet valve control circuit is shorted to ground, meaning the circuit is being pulled low independently of the module driver. Because the module operates the solenoid by switching its low side to ground, an unintended ground path causes uncontrolled current or a fault condition that disables the valve. When thi...

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