P05BF

Symptoms

• The start-stop system does not activate when stopping
• Check Engine light is on
• The information display shows a system fault warning
• The start-stop shutdown button may not respond to pressing
• Slight increase in fuel consumption in traffic jams

Causes

• Short circuit of the switch signal wire to the power line (+12V)
• Damage to wiring insulation with a short to voltage source
• Faulty start-stop switch (sticky contacts)
• Moisture getting into the switch connector
• ECU malfunction (rare cause)

How to Fix

1. Read all fault codes with a diagnostic scanner, record frozen frame data
2. Refer to the service manual for the start-stop switch circuit diagram.
3. Check the wiring from the switch to the ECU for damage, exposed wires, signs of overheating
4. Check the switch connector for moisture, oxidation, or bent contacts.
5. Using a multimeter, measure the voltage on the signal wire of the switch with the ignition on
6. Replace the switch if a fault is detected; if necessary, repair the wiring

Related codes

Error P05BF by Vehicle Brand