P0309 - OBD II Trouble Code

Our automotive experts have put together the following information about the P0309 diagnostic trouble code. We've provided the common symptoms that occur when this code is set along with the frequent repairs that address the issues related to the P0309 code.

What Does P0309 Code Mean?

OBD-II Code P0309 is defined as a Cylinder 9 Misfire Detected

When the engine control module (PCM) detects that cylinder nine is not sufficiently contributing to keeping the engine running properly, it will set code P0309.

P0309 Symptoms

• Decreased engine performance
• Increased fuel consumption

Common Problems That Trigger the P0309 Code

• Damaged or contaminated spark plug
• Engine sensor failure
• Exhaust leak
• Fuel injector failure
• Fuel pump failure
• Ignition coil failure
• Internal engine failure
• Powertrain Control Module (PCM) software needs to be updated
• The fuel does not meet the manufacturer's requirements
• Vacuum leak

Common Repairs Needed for the P0309 Code

• Fuel Injector Replacement
• Ignition Coil Replacement