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AutoCodes – Generic – P0302

P0302 Code - Cylinder 2 Misfire Detected

Quick Answer

The Engine Control Module (ECM) uses information from the crankshaft position sensor and the camshaft position sensor to determine when an engine cylinder misfire is occurring. Common causes include Faulty Spark Plug #2, Clogged or faulty Fuel Injector #2, Faulty Ignition Coil #2. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0302 indicates Cylinder 2 Misfire Detected.
Common causes
Common causes include Faulty Spark Plug #2, Clogged or faulty Fuel Injector #2, Faulty Ignition Coil #2.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code Popularity 129,301
How popular is this code, among other codes? Medium
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Table of contents Created and updated by William Orellana on Jun 13, 2022
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Code P0302 Description

The Engine Control Module (ECM) uses information from the crankshaft position sensor and the camshaft position sensor to determine when an engine cylinder misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the ECM can detect individual cylinder misfire events.
Extreme cylinder misfire events can cause catalytic converter damage. The malfunction indicator lamp (MIL) will flash when the conditions for catalytic converter damage are present. The Diagnostic Trouble Codes (DTC) P0302 correspond to cylinders 2. When the ECM detects that one or more specific cylinders are misfiring, the DTC for the respective misfiring cylinder will set, and up to 2 of the corresponding fuel injectors are disabled for a minimum of 30 s. The ECM will then re-enable the fuel injector and, after approximately 200 engine revolutions, will determine if the misfire is still present. If the misfire is still present, the ECM will disable the fuel injector again repeating the process. If the misfire is not present, the fuel injector will remain enabled by the ECM. In Spark Ignition Direct Injection (SIDI) system applications, if a fuel injector fault DTC is set during a misfire event, the ECM will not re-enable the injector.
OBDII Code P0302 - Cylinder 2 Misfire Detected - AutoCodes.com
P0302 Code - Cylinder 2 Misfire Detected
What does this mean?

What are the Possible Causes of the DTC P0302?

  • Faulty Spark Plug #2
  • Clogged or faulty Fuel Injector #2
  • Faulty Ignition Coil #2
  • Fuel Injector #2 harness is open or shorted
  • Fuel Injector #2 circuit poor electrical connection
  • Ignition Coil #2 harness is open or shorted
  • Ignition Coil #2 circuit poor electrical connection
  • Insufficient cylinder 2 compression
  • Incorrect fuel pressure
  • Intake air leak

How to Fix the DTC P0302?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The P0302 code means that cylinder 2 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder 2. If the problem persists more tests need to be done to diagnose the problem, see "Possible Causes".





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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0302 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0302 code?

Need more information on how to fix the P0302 code? Get Access to Factory Service Manuals

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Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0302 Code

1. What are the common symptoms of OBDII code P0302 (Cylinder 2 Misfire Detected)?

- Common symptoms include rough idling, loss of power, engine vibration, and potential fuel efficiency issues.

2. What are some possible causes of OBDII code P0302?

- Potential causes of a Cylinder 2 misfire can include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, or low compression.

3. How can I diagnose the cause of a Cylinder 2 misfire?

- Diagnosing a Cylinder 2 misfire may involve checking spark plugs, ignition coils, fuel injectors, compression levels, and conducting a visual inspection for any visible issues.

4. Are there any tips for repairing OBDII code P0302?

- Repair tips may include replacing spark plugs, ignition coils, fuel injectors, addressing vacuum leaks, performing a compression test, and clearing the trouble code.

5. Can driving with OBDII code P0302 cause further damage to the engine?

- Continuing to drive with a Cylinder 2 misfire can potentially lead to damage to the catalytic converter, oxygen sensors, and other engine components over time.

6. How urgent is it to address OBDII code P0302 (Cylinder 2 Misfire Detected)?

- It is recommended to address a Cylinder 2 misfire promptly to prevent potential damage to the engine and ensure optimal vehicle performance.

7. Is it safe to drive my vehicle with OBDII code P0302?

- It is generally not recommended to drive with a Cylinder 2 misfire as it can lead to increased emissions, reduced fuel efficiency, and potential damage to the engine.

8. Can weather conditions affect the occurrence of OBDII code P0302?

- Extreme weather conditions such as cold temperatures or high humidity can impact the performance of engine components and contribute to misfires, including Cylinder 2 misfires.

9. How much does it typically cost to repair OBDII code P0302?

- The cost of repairing a Cylinder 2 misfire can vary depending on the specific cause, but it may involve expenses related to parts replacement, labor, and diagnostic fees.

10. Does OBDII code P0302 always indicate a problem with Cylinder 2?

- While the code specifically points to a misfire in Cylinder 2, it is possible for other related issues like a vacuum leak or fuel delivery problem to trigger the same error code.

Discuss the causes and fixes for P0302 OBDII Code

Submit a New Comment

  • I have a 2008 Grand Prix GXP, it was hit in the front driver side. I am
    getting codes p0302. Changed spark plugs. Now getting u0073. Could
    this be the result of being hit?

    Reply to Comment

  • It's possible, but unfortunately we can deduct much from just the codes, you have to inspect the your vehicle and check if there are any harness damage.

    U0073 Pontiac - Control Module Communication Bus OFF

    Read more: https://www.autocodes.com/u00...

    Reply to Comment
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