OBD Guide

P03A8

Cylinder 2 Combustion Performance

P03A8 is an OBD-II diagnostic trouble code meaning: Cylinder 2 Combustion Performance. Common causes: clogged or faulty injector of cylinder 2, worn or carbonated spark plug. Estimated repair cost: $22–278.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$22–278 (est.)

Symptoms

  • Check Engine light on
  • Increased fuel consumption
  • Smell of unburned fuel from the exhaust
  • Unstable operation at idle
  • Reduced dynamic characteristics of the vehicle

Causes

  • Clogged or faulty injector of cylinder 2
  • Worn or carbonated spark plug
  • Weak ignition coil cylinder 2
  • Reduced compression in cylinder 2
  • Incorrect valve timing

How to Fix

  1. Check and, if necessary, replace the spark plug of cylinder 2
  2. Check the ignition coil of cylinder 2 (exchange with another cylinder for testing)
  3. Diagnose cylinder 2 injector - fuel balance, spray
  4. Perform a compression test on cylinder 2
  5. Check valve timing and condition of valves
  6. After repair, reset codes and test drive

Related codes

Error P03A8 by Vehicle Brand

FAQ

What does the P03A8 code mean?

P03A8 is an OBD-II diagnostic trouble code that indicates: Cylinder 2 Combustion Performance

What causes a P03A8 error code?

The most common causes of P03A8 include: Clogged or faulty injector of cylinder 2; Worn or carbonated spark plug; Weak ignition coil cylinder 2; Reduced compression in cylinder 2.

How do I fix a P03A8 diagnostic trouble code?

To fix P03A8: Check and, if necessary, replace the spark plug of cylinder 2. Check the ignition coil of cylinder 2 (exchange with another cylinder for testing). Diagnose cylinder 2 injector - fuel balance, spray. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P03A8?

Do not drive — repair immediately

How much does it cost to fix P03A8?

The estimated repair cost for P03A8 is $22–278. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat