C1199 — ABS Inlet Valve Coil LF Circuit Open

Causes

• Open or broken wiring between ABS module and LF inlet valve coil
• Disconnected, corroded or damaged connector at the LF inlet valve
• Failed LF inlet valve solenoid coil
• Blown fuse or faulty relay supplying the ABS module/valve circuit
• Poor ground or power supply to ABS module
• Faulty ABS control module (less common)

Symptoms

• ABS warning light and possibly Traction Control/ESC warning illuminated
• ABS/traction control may be disabled for affected wheel
• Possible longer stopping distances under ABS operation, reduced ABS function
• No ABS actuation at left‑front wheel (no pulsation under hard braking)

What to check

• Read ABS codes and freeze frame data with a scan tool; record supporting codes
• Perform visual inspection of LF wheel area wiring, harness routing, and connector for damage or corrosion
• Inspect fuses and relays related to ABS power and control circuits
• With ignition ON, backprobe the LF inlet valve connector and check for continuity to ABS module pins
• Use scan tool to command the LF inlet valve ON/OFF while monitoring voltage/current at the valve connector
• Measure coil resistance at the valve connector (with connector disconnected)

Signal parameters

• Expected coil resistance (typical range): ~5–30 Ω (vehicle specific — consult service data)
• Key ON battery voltage present at harness power feed to the valve circuit (when applicable) ~11–14 V
• When commanded by the ABS module the valve sees a pulsed/PWM drive — voltage varies with duty cycle rather than steady 12 V
• Open circuit shows infinite resistance or very high ohms at valve coil terminals
• No voltage change at connector when commanded indicates open between module and valve or module output fault

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