OBD Guide
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P03AF

Cylinder 3 Pressure Too High

P03AF is an OBD-II diagnostic trouble code meaning: Cylinder 3 Pressure Too High. Common causes: detonation due to the use of low octane gasoline, glow ignition (carbon deposits, overheated spark plugs). Estimated repair cost: $56–1111.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–1111 (est.)

Symptoms

  • Detonation knocking noise (metallic sound when accelerating)
  • Check Engine Light with Possible Power Restriction
  • Engine overheating
  • Drop in power and throttle response
  • Engine vibration

Causes

  • Detonation due to the use of low octane gasoline
  • Glow ignition (carbon deposits, overheated spark plugs)
  • Ignition timing too early
  • Engine overheating (cooling system malfunction)
  • EGR (exhaust gas recirculation) valve malfunction

How to Fix

  1. Stop the engine if knocking noises occur—continuing driving is dangerous.
  2. Check coolant temperature, antifreeze level
  3. Make sure you use gasoline with the required octane number
  4. Check the spark plugs of cylinder 3 for carbon deposits and the condition of the electrodes
  5. Check the ignition timing and the operation of the knock sensor
  6. Diagnose the EGR and engine cooling system

Related codes

P03A5P03BCP0303P0324P0325

Error P03AF by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P03AF code mean?

P03AF is an OBD-II diagnostic trouble code that indicates: Cylinder 3 Pressure Too High

What causes a P03AF error code?

The most common causes of P03AF include: Detonation due to the use of low octane gasoline; Glow ignition (carbon deposits, overheated spark plugs); Ignition timing too early; Engine overheating (cooling system malfunction).

How do I fix a P03AF diagnostic trouble code?

To fix P03AF: Stop the engine if knocking noises occur—continuing driving is dangerous.. Check coolant temperature, antifreeze level. Make sure you use gasoline with the required octane number. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P03AF?

Do not drive — repair immediately

How much does it cost to fix P03AF?

The estimated repair cost for P03AF is $56–1111. Actual cost depends on your vehicle, location, and labor rates.

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