DF1015

Code

RENAULT D

-> P0504 - Brake Contact Information Consistency

Brand: RENAULT

Type: D

Views: UK: 4 EN: 7 RU: 5

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty or misadjusted brake light / brake pedal switch (mechanical failure or worn plunger)
Damaged wiring, broken conductor, corroded connector or poor ground in brake switch circuit
Intermittent connection (loose connector) at switch, fuse, or fusebox
Conflicting or corrupted CAN / network messages from another control module
Faulty BCM/ECU or ABS/ESP module reporting incorrect brake status
Incorrect software/calibration or configuration after replacement or update

Symptoms

Cruise control or adaptive cruise unavailable or disengages unexpectedly
Start/stop system disabled or behaves incorrectly
Brake lights stay on, do not illuminate, or flash inconsistently
Warning lights or messages (Brake, ABS, ESP, or check engine) present
Inconsistent vehicle behaviour related to braking input (control interventions)
DTC present and may reappear after clearing if fault persists

What to check

Read all stored and pending DTCs on all modules (engine, ABS, BCM, instrument cluster) and note freeze frame data
Monitor live data: brake switch A/B states, brake pedal position/angle (if present), stop lamp status, and related CAN signals
Visually inspect brake light switch, its plunger, mounting, and alignment with pedal
Inspect wiring harness, connector pins, and grounds for corrosion, breaks, or water intrusion
Check stop lamp fuse(s) and related fuses/relays
Check for CAN bus fault codes or lost communication messages between modules

Signal parameters

Brake switch A (binary: ON/OFF) — terminal voltage at rest and when pressed
Brake switch B (if fitted) — secondary switch state for redundancy
Stop lamp circuit voltage/load when pedal pressed
Brake pedal position sensor or potentiometer value (if equipped)
ABS/ESP brake request or wheel speed deceleration messages on CAN
Module CAN messages: BrakePedalStatus / StopLampStatus as seen in scan tool

Diagnostic algorithm

Connect a capable diagnostic tool and record all related DTCs and live data streams from engine, ABS, BCM and cluster.
Reproduce the fault: observe brake switch A/B status while pressing and releasing the pedal; watch stop lamp status and CAN brake signals for inconsistencies.
Visually inspect the brake switch and its mounting. Confirm the switch plunger fully actuates with pedal travel and is not damaged or contaminated.
Check connector pins for corrosion, bent pins, or water ingress. Wiggle harness while observing live data to detect intermittent changes.
Measure voltage at the switch: verify reference battery supply, ground, and output signal(s) change reliably between rest and pressed positions. Use multimeter or oscilloscope for intermittent cases.
Verify stop lamps operate when pedal pressed; check fuse continuity and lamp filaments/LEDs and associated wiring.
If vehicle has dual brake switches (A/B), compare both outputs for consistent behavior; if only one fitted, check for conflicting CAN messages reporting a different state.
Inspect CAN bus for errors: check module communication, bus voltages, and any network-related DTCs. If another module is reporting incorrect brake state, trace to that module.
If wiring and switch test good, perform module software checks and update/flash if a known calibration issue exists. Consider replacing the brake switch if electrical tests are marginal or intermittent.
After repair or replacement, clear codes and perform road test to confirm fault does not return and systems (cruise, start/stop, brake lights) operate normally.

Likely causes

Brake pedal switch physically out of adjustment or stuck (most common)
Open/short in brake switch wires or connector corrosion
Stop lamp fuse blown or poor ground affecting switch reference
Intermittent CAN bus communication error between BCM/ECU and engine/ABS module
Failed brake switch (electrical contacts degraded) requiring replacement

Fault status

⚠️ Status

DF1015 / P0504 — Brake contact information inconsistent: mismatch between brake pedal switch signals or between switch output and CAN-reported brake status.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-3.0 hours

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DF1015 — -> P0504 - Brake Contact Information Consistency