How severe is fault code C1251?

Serious — Stop or limit driving

OBD Code C1251: ABS Inlet Valve Coil LR Circuit Open

Q: What does OBD code C1251 mean?

ABS Inlet Valve Coil LR Circuit Open. The ABS system's left rear inlet valve coil has lost electrical connection, like a broken wire to a light switch. The ABS cannot modulate brake pressure at that wheel, reducing braking performance and safety.

Q: What are the symptoms of fault code C1251?

ABS warning light illuminated on dashboard, Reduced or no ABS function at left rear wheel, Possible brake pulsation or longer stopping distances

Q: How do I fix OBD fault code C1251?

Inspect and reseat the left rear inlet valve solenoid connector; clean corroded contacts.. Repair or replace damaged or pinched wiring between ECU and left rear inlet valve coil.. Replace the left rear inlet valve solenoid coil if resistance is infinite or wiring is confirmed intact.

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What This Actually Means

In plain language — no jargon

The ABS system's left rear inlet valve coil has lost electrical connection, like a broken wire to a light switch. The ABS cannot modulate brake pressure at that wheel, reducing braking performance and safety.

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Symptoms You May Notice

3 known symptoms for this code

ABS warning light illuminated on dashboard

Reduced or no ABS function at left rear wheel

Possible brake pulsation or longer stopping distances

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Embedded Systems Insight

What the ECU/ECM is actually computing

The ECU monitors the resistance and current draw of the left rear inlet valve solenoid coil during ABS events. It expects a specific impedance range; an open circuit (infinite resistance) indicates a broken coil wire or connector failure. The ECU cannot energize the valve to control brake pressure modulation.

Voltage & Parameter Thresholds

Parameter	Normal Range	Fault Condition
Coil Resistance	4-8 ohms (typical solenoid)	>10K ohms or open circuit
Coil Current Draw	0.5-2 amps during activation	No current or <0.1 amps

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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex

1

ABS connector and wiring harness

Inspect and reseat the left rear inlet valve solenoid connector; clean corroded contacts.

2

ABS wiring harness (LR circuit)

Repair or replace damaged or pinched wiring between ECU and left rear inlet valve coil.

3

ABS inlet valve solenoid (LR)

Replace the left rear inlet valve solenoid coil if resistance is infinite or wiring is confirmed intact.