Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P05FF Brake Pressure Sensor/Brake Pedal Position Sensor Correlation

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Stop-start decides when to stop and restart the engine from the brake: Ford stops it when the pedal switch is on and master cylinder pressure is high enough, and restarts when pressure falls below a filtered reference. P05FF means brake pressure (from the sensor in the ABS unit, sent over the network) and brake pedal position do not agree – for example pedal pressed without pressure build-up, or pressure without pedal. Ford's 2020–23 petrol vehicles check this continuously in the section 'Brake Diagnostics for Stop-Start Dependability' and set the code within 1 s, without the check engine light; stop-start is blocked so the engine is not stopped or started unexpectedly. Ford gives no threshold for the deviation. GM monitors the pedal travel sensor under P057x instead. Brake switch disagreement is P0504.

Likely causes

Brake pedal position sensor or switch misadjusted or faulty
Master cylinder pressure sensor in the ABS unit faulty
Network communication or software between ABS module and engine module
Air in the brake system or hydraulic fault (long pedal travel without pressure)

Symptoms

  • Stop-start disabled
  • No check engine light at Ford, possibly wrench or service warning
  • Possible related codes P0504 or brake pressure codes

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–1,500
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

brake pressure sensorbrake pedal position sensorabs control module

Related codes

P0504P0571P0572P0573P05E0P057B

References: law.cornell.edu, fordservicecontent.com, patents.google.com.