What Does P0573 Mean?
The ECM has detected that the cruise control brake switch 'A' circuit is stuck in the high (open/inactive) state, indicating the brake pedal appears to never be pressed. This means the cruise control system does not receive a brake-applied signal when the driver steps on the brake pedal, which is a critical safety input for canceling cruise control during braking.
Common Causes
35%
Faulty brake light switch with open internal contacts that never close when the brake pedal is pressed
25%
Open circuit in the brake switch signal wire between the switch and ECM preventing the brake signal from being transmitted
25%
Brake light switch misadjusted too far from the brake pedal so the plunger never closes the contacts when the pedal is pressed
15%
Disconnected brake switch connector or backed-out connector pins
Diagnostic Steps
1
Step 1: Check brake light operation. If brake lights do not illuminate when the pedal is pressed, the switch circuit is open. This confirms the fault and also creates a safety hazard independent of cruise control.
2
Step 2: Inspect the brake switch connector at the top of the brake pedal arm. Verify it is fully connected and the locking tab is engaged. Check for backed-out pins or corrosion.
3
Step 3: With the brake pedal pressed, measure the switch contact for continuity. The circuit should be closed (near 0 ohms) when the pedal is pressed. An open reading confirms switch failure.
4
Step 4: Check brake switch adjustment. The switch plunger must contact and be depressed by the brake pedal arm when the pedal is released, and extend when the pedal is pressed (or vice versa depending on design). Readjust if needed.
5
Step 5: If the switch operates correctly, check for an open in the signal wire from the switch to the ECM. Verify continuity end-to-end and repair any open circuits found.
Estimated Repair Cost
$15 - $120
Parts + labor, varies by vehicle and location
The ECM has detected that the cruise control brake switch 'A' circuit is stuck in the high (open/inactive) state, indicating the brake pedal appears to never be pressed. This means the cruise control system does not receive a brake-applied signal when the driver steps on the brake pedal, which is a ...
The most common cause of P0573 (Cruise Control/Brake Switch A Circuit High) is: Faulty brake light switch with open internal contacts that never close when the brake pedal is pressed
Typical repair costs for P0573 range from $15 to $120, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This is a significant safety concern because cruise control may not cancel when the brake pedal is pressed. While most systems have redundant cancel methods (clutch switch, multiple brake inputs), the primary cancel-on-brake function is compromised. Additionally, non-functional brake lights endanger following traffic.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0573 to identify the root cause.
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Quick Info
Category
Powertrain
System
Cruise Control / Brake System Interface
Difficulty
Type
Generic (SAE)
Recommended Tools
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