P0572
Cruise Control/Brake Switch A Circuit Malfunction
Powertrain Chassis/Safety Brake Switch Circuit 🟡 Moderate — Fix within a week
💬
What This Actually Means
In plain language — no jargon

Your car's cruise control brake switch isn't communicating properly with the engine computer. Think of it like a light switch that's stuck or broken—the ECU can't tell if you're pressing the brake pedal or not.

⚡
Symptoms You May Notice
3 known symptoms for this code
Cruise control won't engage or suddenly disengages
Brake lights may not function properly
Check Engine Light illuminated
🔬
Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors voltage levels from the brake switch circuit to detect when the brake pedal is pressed. When brakes are applied, the switch should signal the ECU to deactivate cruise control immediately. The ECM checks for proper voltage transitions and circuit continuity to ensure safe operation.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Brake Switch Voltage 0V when pedal pressed, 5V when released No voltage change or stuck at one level
Circuit Resistance Less than 5 ohms when engaged Open circuit (infinite ohms) or short condition
🔧
Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Brake Pedal Switch
Locate the switch under the dash at the brake pedal, unplug the connector, and test continuity with a multimeter before replacement.
2
Wiring Harness and Connectors
Inspect the brake switch connector and wiring for corrosion, loose pins, or damage; clean contacts with electrical cleaner or replace if needed.
3
Cruise Control Module Connector
Check the cruise control stalk and related connectors on the steering column for loose or corroded connections.