When your 2021 Jeep Gladiator displays the P0305 code, the engine control module has detected repeated misfires in cylinder 5. The 2021 Gladiator uses the 3.6L Pentastar V6 as its standard gasoline engine. With six cylinders numbered 1-6, P0305 is a legitimate diagnostic code.
2021 Gladiator Powertrain
The 2021 Gladiator offers the 3.6L Pentastar V6 (285 hp) or the 3.0L EcoDiesel V6 (260 hp). Both are six-cylinder engines with a cylinder 5, making P0305 valid on all Gladiator configurations.
Cylinder 5 Location
On the 3.6L Pentastar V6, cylinder 5 is on the driver side (left bank) toward the rear. Stellantis positions odd-numbered cylinders on the driver side. Access may require removing the air intake or engine cover.
Common Causes
Spark plug wear is common, especially with towing or off-road use. Ignition coil failure at cylinder 5 is possible. Fuel injector issues can cause lean misfires. Vacuum leaks around the intake affect cylinder performance.
Diagnostic Process
Read all codes and freeze frame data. Access cylinder 5's spark plug and inspect. Test the ignition coil. Check for vacuum leaks. Verify fuel injector operation.