When your 2024 GMC Terrain displays the P0303 code, the powertrain control module has identified consistent misfires in cylinder 3. The 2024 Terrain continues with GM's efficient 1.5L turbocharged four-cylinder engine.
Engine Configuration
The 2024 Terrain's 1.5L turbocharged inline-4 positions cylinder 3 as the third cylinder from the timing chain end. This compact crossover's engine uses direct fuel injection and turbocharging for optimal power and efficiency.
Typical Causes
- Ignition Coil Problems: Coil-on-plug design allows isolated failures
- Spark Plug Condition: Turbo engines stress spark plugs more than naturally aspirated
- Fuel Injector Issues: Direct injection system deposits or failures
- Turbo System Integrity: Boost leaks cause lean misfires
- Carbon Deposits: GDI technology leads to valve carbon accumulation
Diagnostic Steps
Connect a scan tool to review misfire data and freeze frame information. Monitor boost pressure and fuel trim values. Perform ignition component testing. Check for vacuum and boost leaks using appropriate methods.
Repair Solutions
Replace faulty ignition coils or spark plugs with GM-specified parts. Repair boost system leaks identified during diagnosis. Clean or replace fuel injectors as needed. Professional carbon cleaning addresses valve deposits.