OBD Guide
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P0091

Fuel Pressure Regulator A Control Circuit Low

P0091 is an OBD-II diagnostic trouble code meaning: Fuel Pressure Regulator A Control Circuit Low. Common causes: faulty fuel pressure regulator, damaged wires in the control circuit. Estimated repair cost: $17–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–167 (est.)

Symptoms

  • Unstable engine operation at idle
  • Difficulty starting the engine
  • Increased fuel consumption
  • Loss of power when accelerating
  • Check Engine Light Illuminated
  • Jerks when moving
  • Black smoke from the exhaust pipe

Causes

  • Faulty fuel pressure regulator
  • Damaged wires in the control circuit
  • Oxidation or corrosion of connectors
  • Faulty engine control unit
  • Short circuit in wiring
  • Poor circuit grounding
  • Faulty fuel pressure sensor
  • Problems with the fuel system relay

How to Fix

  1. Connect the diagnostic scanner and read the error codes
  2. Check the voltage in the fuel pressure regulator control circuit
  3. Inspect wiring for damage, corrosion or short circuit
  4. Clean and check all connectors in the circuit
  5. Check the resistance and integrity of the wires with a multimeter
  6. Measure the fuel pressure in the system with a pressure gauge
  7. Replace a faulty fuel pressure regulator if necessary
  8. Check and, if necessary, replace damaged wiring
  9. Clear error memory and test drive

Related codes

P0087P0088P0089P0090P0092P0093P0094P0190

Error P0091 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0091 code mean?

P0091 is an OBD-II diagnostic trouble code that indicates: Fuel Pressure Regulator A Control Circuit Low

What causes a P0091 error code?

The most common causes of P0091 include: Faulty fuel pressure regulator; Damaged wires in the control circuit; Oxidation or corrosion of connectors; Faulty engine control unit.

How do I fix a P0091 diagnostic trouble code?

To fix P0091: Connect the diagnostic scanner and read the error codes. Check the voltage in the fuel pressure regulator control circuit. Inspect wiring for damage, corrosion or short circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0091?

Limited driving only, diagnose soon

How much does it cost to fix P0091?

The estimated repair cost for P0091 is $17–167. Actual cost depends on your vehicle, location, and labor rates.

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