C1203
ABS Outlet Valve Coil Rear Circuit Open
Chassis Chassis/Safety ABS valve circuit 🔴 Serious — Stop or limit driving
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What This Actually Means
In plain language — no jargon

The ABS system's rear outlet valve coil has a broken electrical connection, like a light switch with a severed wire. The ECU can't send power to activate the valve, so the rear brakes can't be modulated during ABS events.

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Symptoms You May Notice
3 known symptoms for this code
ABS warning light illuminated on dashboard
Loss of ABS function; brakes lock up under hard braking
Possible extended stopping distances in emergency braking
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU sends a signal to energize the rear ABS outlet valve coil to modulate brake pressure. It monitors the coil circuit's resistance and current draw during activation. An open circuit means infinite resistance and zero current flow, triggering the fault.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Coil Resistance 5-15 ohms Infinite ohms (open circuit)
Coil Current Draw 0.5-2.0 amps 0 amps or no response
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
ABS rear outlet valve connector
Clean and reseat the connector at the valve to restore electrical continuity; check for corrosion or bent pins.
2
ABS valve wiring harness
Inspect the wiring from the ABS module to the rear outlet valve for breaks, cuts, or pinches and repair or replace as needed.
3
Rear ABS outlet valve assembly
Replace the valve if the internal coil is open or the connector cannot be repaired.