how to fix P0304 code in Tesla Model 3 Original (2017-2023)

Tesla Model 3 Highland (2024-present)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

Error Code: P0304

3 min read

574 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix P0304 cylinder 4 misfire in Tesla Model 3. Step-by-step guide with diagnostic procedures and repair instructions.

Error Code

P0304

Affected Component

Engine

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 starting any work.

Symptoms

•Check engine light illuminated
•Rough idle
•Decreased fuel efficiency
•Engine stalling or hesitation during acceleration
•Increased exhaust emissions
•Unusual engine sounds (e.g., popping or backfiring)

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0304 and check for any additional codes.
2
Inspect the spark plug in cylinder 4 for wear or damage.
3
Check the ignition coil for proper operation and any signs of failure.
4
Evaluate the fuel injector in cylinder 4 for clogs or malfunctions.
5
Perform a compression test on cylinder 4 to check for mechanical issues.
6
Inspect wiring and connections related to the ignition system and fuel injector.

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
•Spark plug socket
•Ratchet
•Torque wrench
•Gap gauge
•Compression tester
•Injector cleaning kit

Parts Required

•Spark plug (specific to Tesla Model 3)
•Ignition coil (specific to Tesla Model 3)
•Fuel injector (if needed)

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0304 and check for any additional codes.
2
Inspect the spark plug in cylinder 4 for wear or damage.
3
Check the ignition coil for proper operation and any signs of failure.
4
Evaluate the fuel injector in cylinder 4 for clogs or malfunctions.
5
Perform a compression test on cylinder 4 to check for mechanical issues.
6
Inspect wiring and connections related to the ignition system and fuel injector.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the vehicle's battery to prevent electrical shorts.
Allow the engine to cool down before beginning work.

2. Inspect and Replace Spark Plug

Tools Required: Spark plug socket, ratchet, torque wrench, gap gauge.
Remove the ignition coil from cylinder 4 by unscrewing the bolts and disconnecting the electrical connector.
Remove the spark plug using the spark plug socket and ratchet.
Inspect the spark plug for wear or damage and replace if necessary. Ensure the gap is set according to manufacturer specifications.
Install the new or inspected spark plug and torque it to the manufacturer’s specifications (typically around 15-20 ft-lbs).

3. Check and Replace Ignition Coil

Inspect the ignition coil for cracks or signs of wear.
If faulty, remove the ignition coil by unscrewing it and disconnecting the electrical connector.
Install a new ignition coil and reconnect the electrical connector securely. Ensure it is seated properly.

4. Inspect and Clean Fuel Injector

Use an injector cleaning kit to clean the fuel injector for cylinder 4 or replace it if necessary.
Remove the fuel rail if required to access the injector.
Install the cleaned or new injector and ensure it is seated properly.

5. Perform Compression Test

Reconnect the battery.
Use a compression tester to check the compression of cylinder 4.
If compression is low, further investigation may be needed for internal engine issues (e.g., valve problems, head gasket failure).