2003 Pontiac Sunfire AutomaticFACTORY OEM SERVICE PROCEDURE

Engine Controls Self-Diagnostics - 2.2L: Introduction

NOTE: If vehicle is equipped with CNG, see SELF-DIAGNOSTICS - 2.2L CAVALIER - BI-FUEL - CNG/GASOLINE article.

To properly diagnose and repair this vehicle, begin with DIAGNOSTIC STARTING POINT - ENGINE CONTROLSΒ  under SELF-DIAGNOSTIC SYSTEM. If no Diagnostic Trouble Codes (DTC) are present and a no start condition exists, proceed to NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. If no DTCs are present and a driveability condition exists, proceed to TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.