OBD Guide
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P05BC

Stop-Start Mode Switch Circuit/Open

P05BC is an OBD-II diagnostic trouble code meaning: Stop-Start Mode Switch Circuit/Open. Common causes: broken wire in the switch circuit, disconnected or oxidized switch connector.

Severity
✅ Low
Can you drive?
Do not drive — repair immediately

Symptoms

  • Check Engine light on
  • The start-stop shutdown button does not respond
  • The start-stop system can be permanently switched on or off
  • The start-stop indicator may not display the correct status
  • Inability to manually disable or enable the system

Causes

  • Broken wire in the switch circuit
  • Disconnected or oxidized switch connector
  • Malfunction (break) of the internal contact of the switch
  • Damage to the wiring harness under the instrument panel
  • Malfunction of the body control module (BCM) processing the signal

How to Fix

  1. Read error codes and check for related codes on the BCM
  2. Check the start-stop switch connector for reliable connection and oxidation
  3. Measure the resistance of the switch in different positions (normally: ~0 Ohm - pressed, infinity - released, or vice versa)
  4. Check the supply voltage at the switch
  5. Inspect the wiring harness from the switch to the BCM for an open.
  6. Replace the switch or repair the wiring based on the results

Related codes

P05BDP0A67P0A68

Error P05BC by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P05BC code mean?

P05BC is an OBD-II diagnostic trouble code that indicates: Stop-Start Mode Switch Circuit/Open

What causes a P05BC error code?

The most common causes of P05BC include: Broken wire in the switch circuit; Disconnected or oxidized switch connector; Malfunction (break) of the internal contact of the switch; Damage to the wiring harness under the instrument panel.

How do I fix a P05BC diagnostic trouble code?

To fix P05BC: Read error codes and check for related codes on the BCM. Check the start-stop switch connector for reliable connection and oxidation. Measure the resistance of the switch in different positions (normally: ~0 Ohm - pressed, infinity - released, or vice versa). For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P05BC?

Do not drive — repair immediately

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See also: Russian version · NationStat