how to fix P0302 code in BMW 5 Series G30/G31 (2017-2024)

BMW 5 Series G30/G31 (2017-2024)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

Error Code: P0302

3 min read

553 words

Problem Statement

The P0302 code indicates a misfire detected in cylinder 2 of a BMW 5 Series G30/G31 (2017-2024). This issue can lead to poor engine performance and increased emissions.

Error Code

P0302

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow the engine to cool before removing any components.

Symptoms

•Check engine light illuminated
•Rough idle or engine shaking
•Decreased acceleration or power
•Poor fuel economy
•Engine stalling during idle or low RPMs

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0302 and check for any additional codes.
2
Inspect the spark plug in cylinder 2 for wear, damage, or fouling.
3
Check the ignition coil for cylinder 2 for functionality and signs of damage.
4
Perform a compression test on cylinder 2 to ensure proper compression levels.
5
Inspect fuel injector operation for cylinder 2 by performing a balance test.
6
Verify the engine's vacuum system for leaks that may affect cylinder performance.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Socket set
•Torque wrench
•Multimeter
•Compression tester

Parts Required

•Spark plug (NGK ILZKR7B8D)
•Ignition coil (Bosch 0221504472)
•Fuel injector (Siemens 13537597853)

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0302 and check for any additional codes.
2
Inspect the spark plug in cylinder 2 for wear, damage, or fouling.
3
Check the ignition coil for cylinder 2 for functionality and signs of damage.
4
Perform a compression test on cylinder 2 to ensure proper compression levels.
5
Inspect fuel injector operation for cylinder 2 by performing a balance test.
6
Verify the engine's vacuum system for leaks that may affect cylinder performance.

Solution

1. Preparation

Gather all necessary tools and parts.
Disconnect the battery to prevent any electrical short circuits.

2. Replace Spark Plug

Remove the engine cover if applicable.
Locate the spark plug for cylinder 2.
Use a socket wrench to carefully remove the spark plug.
Inspect the electrode for wear and replace with a new spark plug (specifications: NGK P/N: ILZKR7B8D).
Torque the new spark plug to manufacturer specifications (typically around 20 Nm).

3. Inspect and Replace Ignition Coil

Disconnect the electrical connector from the ignition coil for cylinder 2.
Remove the ignition coil using a socket wrench.
Inspect the coil for cracks or damage; replace if necessary (compatible part: Bosch 0221504472).
Reinstall the new ignition coil and reconnect the electrical connector.

4. Test and Replace Fuel Injector (if necessary)

Disconnect the fuel line and electrical connector from the fuel injector for cylinder 2.
Remove the fuel injector using appropriate tools.
Test the injector's operation with a multimeter or replace it if faulty (compatible part: Siemens P/N: 13537597853).
Reinstall the new fuel injector ensuring proper seating and reconnect the electrical connector.

5. Check for Vacuum Leaks

Inspect vacuum hoses around the intake manifold for cracks or disconnections.
Replace any damaged hoses to ensure proper vacuum levels.

6. Reconnect Battery and Clear Codes

Reconnect the car battery.
Use the OBD-II scanner to clear the P0302 code and any other stored codes.