P0309 OBD-II Trouble Code: Cylinder 9 Misfire Detected

Our certified mechanics come to you · 12-month, 12,000-mile warranty

SCHEDULE P0309 DIAGNOSTIC Get a fair and transparent estimate upfront
Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0309 code

P0309 is a diagnostic trouble code (DTC) for "Cylinder 9 Misfire Detected". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$70.00$30.00
Toyota$70.00$30.00
BMW$70.00$30.00
SCHEDULE P0309 DIAGNOSTIC Get a fair and transparent estimate upfront

Check Engine Light

P0309 code definition

When the P0309 trouble code appears, it means that the powertrain control module has found a misfire from cylinder number 9.

What the P0309 code means

When this code appears, it means that the vehicle’s computer has found one of the engine cylinders is not firing properly.

What causes the P0309 code?

Potential causes of the trouble code:

  • Burned exhaust valve
  • Faulty catalytic converter
  • Poor compression
  • Running out of fuel
  • Faulty coil
  • Faulty oxygen sensor
  • Faulty fuel injector
  • Faulty wiring
  • Faulty spark plug
  • Defective onboard computer, although this is rare

What are the symptoms of the P0309 code?

There are a number of symptoms that could be caused by the P0309 code. In many cases, the service engine soon lamp will illuminate. In addition to the stored code, the vehicle may have a rough idle and the acceleration may feel choppy. The driver may also notice that there is a reduced amount of power in the vehicle. Some also find that the vehicle is more difficult to start.

How does a mechanic diagnose the P0309 code?

When the mechanic is trying to diagnose the P0309 code, he or she will attach their OBD-II scanner to the vehicle’s onboard computer. They will then scan for the code and any other codes that may be stored in the vehicle. At that point, they will reset the code and drive the vehicle to see if the codes return.

If the code returns, then they know it is a problem that they will need to fix. They will then start to look at all the other potential problems that could be causing the code to be stored, such as faulty fuel injectors, bad wiring, or a problematic catalytic converter.

Common mistakes when diagnosing the P0309 code

When this code presents itself, some mechanics may believe that the problem lies in the ignition system rather than other areas. While it is possible for the ignition system to be a fault, there are also other factors that could cause this misfire of the cylinder. It is important for the mechanics to look at all of the potential areas that could be causing problems and find the correct solution for the vehicle.

How serious is the P0309 code?

While the stored code and a service light that illuminates might not seem like a big problem, there are other potential issues with the P0309 code. Drivers who are in vehicles that do not accelerate properly when they are driving could be in danger. Any vehicle that is not performing properly has the potential to cause an accident. The best course of action is to take the vehicle to a mechanic who can diagnose it and make the proper repairs. This is true no matter what code has been stored.

What repairs can fix the P0309 code?

The following are some of the potential fixes that mechanics will attempt when trying to deal with the misfired cylinder number 9.

Additional comments for consideration regarding the P0309 code

The P0309 code, as with all trouble codes, is nothing to ignore. Take the vehicle to a mechanic to have it diagnosed and repaired properly as soon as possible.

Need help with a P0309 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
Check Engine Light
P0309

Fast and easy Check Engine Light is on Inspection service at your home or office.

SCHEDULE P0309 DIAGNOSTIC
Get a fair and transparent estimate upfront

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.5/5

Number of Reviews

3,936

Rating Summary
3,597
169
44
25
101
3,597
169
44
25
101

Alexis

27 years of experience
74 reviews
Alexis
27 years of experience
Professional and knowledgeable.
2010 VOLKSWAGEN GTI - CHECK ENGINE LIGHT IS ON - MIAMI, FLORIDA

Emmette

33 years of experience
269 reviews
Emmette
33 years of experience
Answered all my questions . Very Pleasant to talked to . Completely satisfied .
2006 NISSAN 350Z - CHECK ENGINE LIGHT IS ON - WOODBRIDGE, VIRGINIA

Jamahl

17 years of experience
703 reviews
Jamahl
17 years of experience
Excellent service
2014 DODGE GRAND CARAVAN - CHECK ENGINE LIGHT IS ON - WINTER GARDEN, FLORIDA

TJ

23 years of experience
236 reviews
TJ
23 years of experience
Perfect 10 plus
2007 FORD MUSTANG - CHECK ENGINE LIGHT IS ON - NORTH PORT, FLORIDA

More related articles

How to Find the Keyless Code on a Ford Explorer or Mercury Mountaineer
Many Ford Explorers and Mercury Mountaineers were manufactured with an option known as the Ford keyless entry keypad. Some models refer to it as SecuriCode as well. It...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...

Related questions

Q: Code is P02990 what does it mean?

Hello, thanks for writing in about your Buick Cascada. Trouble code P0990 is a transmission fluid pressure fault. Possibly an internal fault in the transmission or there is a fluid leak. If the car didn't make it home, I suggest...

Q: ABS Light, DSTC light, and Check Engine Light came on randomly today and car won't start

Hello and thank you for contacting YourMechanic. The DSTC has been temporarily switched off due to high brake temperature. The system will automatically switch on again when the brakes have cooled. If the system has been switched off due to...

Q: Car starts hard and occasionally stalls out. Smells like gas when running.

Hello. If you have poor connections at the ignition coils then that will cause cylinder misfires. These loose connections can also shorten the life of the ignition coils. The connectors need to be replaced in order to ensure that there...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1-800-701-6230 · hi@yourmechanic.com