OBD Guide
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P0387

Crankshaft Position Sensor B Circuit Low

P0387 is an OBD-II diagnostic trouble code meaning: Crankshaft Position Sensor B Circuit Low. Common causes: short circuit of the sensor signal wire to ground, no power supply to the sensor (open circuit). Estimated repair cost: $22–89.

Severity
🚨 Critical
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$22–89 (est.)

Symptoms

  • The engine does not start or starts with great difficulty
  • Unstable operation, frequent engine stops
  • No spark or injection
  • Check Engine Light Is On
  • The ECU may go into emergency mode

Causes

  • Short circuit of the sensor signal wire to ground
  • No power supply to the sensor (open circuit)
  • Air gap too large (sensor misaligned)
  • Faulty sensor (internal failure)
  • Sensor contamination blocking magnetic flux

How to Fix

  1. Read error codes, check sensor parameters at idle
  2. Check the sensor supply voltage (standard: 5V or 12V depending on the type)
  3. Check the signal wire for short circuit to ground (resistance between signal and ground should be high)
  4. Check the air gap between the sensor and the drive disk
  5. Check the sensor with an oscilloscope while cranking with the starter
  6. Replace crankshaft sensor B

Related codes

P0386P0388P0335P0336P0337P0338

Error P0387 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0387 code mean?

P0387 is an OBD-II diagnostic trouble code that indicates: Crankshaft Position Sensor B Circuit Low

What causes a P0387 error code?

The most common causes of P0387 include: Short circuit of the sensor signal wire to ground; No power supply to the sensor (open circuit); Air gap too large (sensor misaligned); Faulty sensor (internal failure).

How do I fix a P0387 diagnostic trouble code?

To fix P0387: Read error codes, check sensor parameters at idle. Check the sensor supply voltage (standard: 5V or 12V depending on the type). Check the signal wire for short circuit to ground (resistance between signal and ground should be high). For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0387?

Do not drive — repair immediately

How much does it cost to fix P0387?

The estimated repair cost for P0387 is $22–89. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat