C0002 — Control of the control key of traction - channel B, valve 1

Causes

• Open or short in the wiring to traction control valve (Channel B, Valve 1)
• Corroded or loose connector at the valve or ABS modulator
• Failed valve solenoid or internal hydraulic/mechanical blockage
• Faulty ABS/traction control module driver circuit
• Blown fuse or poor power/ground to the ABS module
• Contamination or corrosion in the hydraulic control unit

Symptoms

• ABS and/or traction control warning lamp illuminated
• Reduced or disabled traction control and/or ABS functionality
• Stored ABS/traction DTCs related to valve/channel
• Possible abnormal brake feel or pulsation under ABS operation
• Vehicle may enter reduced-performance or limp mode depending on strategy

What to check

• Read ABS/traction control module for current and stored codes and freeze frame data
• Perform visual inspection of wiring harness, connector, and ABS modulator for damage or corrosion
• Check fuses and main power/ground to ABS/traction control module
• Backprobe connector at the valve and verify supply voltage and switching signal while commanding the valve
• Measure solenoid coil resistance at the valve connector (compare to specification)
• Use a scan tool to command the valve and observe module outputs and live data

Signal parameters

• Supply voltage: typically battery voltage (~12 V) present at the ABS modulator power input; verify vehicle-specific data
• Control signal: module usually uses a low-side driver or PWM to control valve — expected switching between ~0 V and battery voltage (or PWM pulses)
• Solenoid resistance: commonly in the low ohm range (example 5–50 Ω depending on model) — consult vehicle service data for exact spec
• When commanded ON the valve coil should show current draw and valve may click; absence of change suggests open/failed coil or driver fault

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