AutoCodes – MINI – P0303 MINI

P0303 MINI Code - Misfire Cylinder 3

Quick Answer

When a misfire occurs, engine speed will fluctuate. Common causes include Faulty Spark Plug #3, Clogged or faulty Fuel Injector #3, Faulty Ignition Coil #3. 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: P0303 MINI indicates Misfire Cylinder 3 .
Common causes: Common causes include Faulty Spark Plug #3, Clogged or faulty Fuel Injector #3, Faulty Ignition Coil #3.
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 14,764

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0303 MINI Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

OBDII Code P0303 MINI - Misfire Cylinder 3 - AutoCodes.com — P0303 MINI Code - Misfire Cylinder 3

What does this mean?

What are the Possible Causes of the DTC P0303 MINI?

Faulty Spark Plug #3
Clogged or faulty Fuel Injector #3
Faulty Ignition Coil #3
Fuel Injector #3 harness is open or shorted
Fuel Injector #3 circuit poor electrical connection
Ignition Coil #3 harness is open or shorted
Ignition Coil #3 circuit poor electrical connection
Insufficient cylinder 3 compression
Incorrect fuel pressure
Intake air leak

How to Fix the DTC P0303 MINI?

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 P0303 code means that the cylinder 3 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 3. If the problem persists more tests needs to be done to diagnose problem, see "Possible Causes"

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0303 MINI 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.

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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 P0303 MINI Code

1. What are the common symptoms of OBDII code P0303 (Misfire Cylinder 3) in a MINI?

- Common symptoms include engine misfiring, rough idle, loss of power, and potential engine vibrations.

2. What are the possible causes of OBDII code P0303 in a MINI?

- Possible causes include faulty spark plugs, ignition coil issues, vacuum leaks, fuel delivery problems, or a malfunctioning fuel injector.

3. How can I diagnose the cause of OBDII code P0303 in my MINI?

- Diagnose by checking spark plugs, ignition coils, fuel injectors, vacuum lines, and performing a compression test to pinpoint the issue.

4. Can driving with OBDII code P0303 (Misfire Cylinder 3) cause further damage to my MINI?

- Continuing to drive with a misfire can potentially damage the catalytic converter and other engine components, leading to costly repairs.

5. How can I repair OBDII code P0303 in my MINI?

- Repair options include replacing spark plugs, ignition coils, fuel injectors, fixing vacuum leaks, and performing a thorough engine tune-up.

6. Is it safe to continue driving my MINI with OBDII code P0303?

- It is not recommended to drive with a misfire as it can lead to decreased fuel efficiency, engine damage, and potential safety hazards.

7. Can a dirty or clogged fuel injector cause OBDII code P0303 in a MINI?

- Yes, a dirty or clogged fuel injector can disrupt the fuel delivery to the cylinder, leading to a misfire and triggering the P0303 code.

8. How important is it to address OBDII code P0303 promptly in my MINI?

- It is crucial to address code P0303 promptly to prevent further engine damage, improve performance, and maintain the overall health of your MINI.

9. Will resetting the OBDII code P0303 by disconnecting the battery fix the issue in my MINI?

- Resetting the code by disconnecting the battery may temporarily clear the warning light, but it will not fix the underlying issue causing the misfire.

10. Can extreme weather conditions affect the occurrence of OBDII code P0303 in a MINI?

- Yes, extreme weather conditions such as extreme cold or heat can impact the engine's performance and potentially trigger misfires leading to code P0303.