Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / P0572 — Cruise Control/Brake Switch A Circuit Low

P0572 — Cruise Control/Brake Switch A Circuit Low

Detailed page for trouble code P0572.

33,912codes
59brands
11,451generic
22,461specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

P0572

MERCEDES-BENZ P — Powertrain

Cruise Control/Brake Switch A Circuit Low

Brand: MERCEDES-BENZ
Type: P — Powertrain
Views: UK: 31 EN: 49 RU: 35
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Short to ground on Brake Switch A signal circuit
  • Failed or sticking brake light / brake pedal switch (switch A)
  • Corroded/loose connector or damaged wiring (open or short)
  • Faulty ground at switch or module
  • Blown or poor fuse / poor power feed to related circuits
  • Faulty control module (rare)

Symptoms

  • Cruise control inoperative or cancels immediately when engaged
  • Brake lights may be stuck ON or not illuminate (depending on failure)
  • Brake warning or related dash message
  • Possible inability to shift out of park in some models (brake pedal switch used for interlocks)
  • DTC stored and lamp (MIL) may be on

What to check

  • Retrieve freeze frame and live data for Brake Switch A status with scan tool
  • Verify brake light operation by observing bulbs while pressing/releasing pedal
  • Visually inspect brake switch, connector, and harness for corrosion, damage, or pinched wires
  • Backprobe switch connector and measure voltage/ground with key ON (engine off) while operating pedal
  • Check for short to ground between the signal wire and chassis ground
  • Inspect related fuses and power feeds

Signal parameters

  • Nominal: Brake Switch A signal = LOW ~0 V when closed/activated (varies by model)
  • Nominal: Brake Switch A signal = HIGH ~5 V or ~12 V (vehicle-dependent) when released
  • Fault condition: persistent ~0 V (low) at module input when pedal released or unexpected state
  • Resistance: Continuity between switch common and ground when pedal activated (model dependent)

Diagnostic algorithm

  1. Connect a capable scan tool, read and record freeze frame and live data for Brake Switch A. Note whether the input reads low continuously or only under certain conditions.
  2. Verify brake lamp function by observing bulbs with key ON while operating the pedal. If brake lights do not behave correctly, suspect the switch or wiring.
  3. Visually inspect the brake switch, mounting, connector and wiring for damage, corrosion, loose pins, or moisture. Repair any obvious issues.
  4. Backprobe the brake switch connector. With ignition ON (engine off), measure voltage on the Brake Switch A signal wire at the switch and at the control module connector. Compare readings. Expect a pull-up voltage (~5 V or ~12 V) when switch is open and ~0 V when closed; a constant ~0 V indicates a low/short to ground.
  5. If signal is low at the module but correct at the switch, check continuity of the signal wire to find a short to ground or damaged conductor; repair wiring/connector as needed.
  6. If signal is low at the switch, disconnect the switch and check for short to ground between the switch terminal and chassis ground. If short remains, trace and repair harness; if short clears with switch disconnected, replace the switch.
  7. After repairs, clear DTCs and road-test to confirm the code does not return and cruise/brake light behavior is normal.
  8. If wiring and switch check good but fault persists, inspect module grounds and power supplies. As a last step, consider module input fault and consult manufacturer-specific procedures before replacing the module.

Likely causes

  • Brake light switch internal failure (contacts shorted or stuck)
  • Pinched or chafed wiring where harness passes under dash or through bulkhead
  • Water intrusion/corrosion at switch connector or junction
  • Short-to-ground in splice or connector near the pedal area
  • Intermittent/open ground or poor terminal contact at module

Fault status

⚠️ Status
Control module detected a low voltage on the Cruise Control / Brake Switch A input circuit (signal near ground). This condition deactivates cruise control and stores DTC P0572. The cause is usually a short to ground, faulty brake light switch, or wiring/connectors between the switch and module.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

P0571 P0573 P0574
133

Browse 133 MERCEDES-BENZ manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MERCEDES-BENZ

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .