OBD Guide
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P03B4

Cylinder 4 Pressure Sensor Circuit Range/Performance

P03B4 is an OBD-II diagnostic trouble code meaning: Cylinder 4 Pressure Sensor Circuit Range/Performance. Common causes: faulty cylinder 4 pressure sensor (misadjustment, performance drift), damage to the wiring or sensor connector. Estimated repair cost: $44–167.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$44–167 (est.)

Symptoms

  • Check Engine light on
  • Minor misfire or erratic operation
  • Slight reduction in engine power
  • Slight degradation in fuel economy
  • Increased emissions during inspection

Causes

  • Faulty cylinder 4 pressure sensor (misadjustment, performance drift)
  • Damage to the wiring or sensor connector
  • Sensor contamination (carbon deposits, oil)
  • Problems with power or grounding of the sensor circuit
  • Cylinder 4 mechanical problems affecting signal

How to Fix

  1. Compare cylinder 4 sensor readings with other cylinders via data scanner
  2. Check the wiring and connector of the sensor for damage
  3. Check signal quality with an oscilloscope
  4. Clean the sensor connector and check the contacts
  5. Replace cylinder 4 pressure sensor
  6. Check compression and other parameters of cylinder 4 to exclude mechanical causes

Related codes

P03B3P03BCP0304P039C

Error P03B4 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P03B4 code mean?

P03B4 is an OBD-II diagnostic trouble code that indicates: Cylinder 4 Pressure Sensor Circuit Range/Performance

What causes a P03B4 error code?

The most common causes of P03B4 include: Faulty cylinder 4 pressure sensor (misadjustment, performance drift); Damage to the wiring or sensor connector; Sensor contamination (carbon deposits, oil); Problems with power or grounding of the sensor circuit.

How do I fix a P03B4 diagnostic trouble code?

To fix P03B4: Compare cylinder 4 sensor readings with other cylinders via data scanner. Check the wiring and connector of the sensor for damage. Check signal quality with an oscilloscope. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P03B4?

Do not drive — repair immediately

How much does it cost to fix P03B4?

The estimated repair cost for P03B4 is $44–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat