how to address P0303 code on Toyota Corolla E170 (2013-2019)

Toyota Corolla E170 (2013-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

Error Code: P0303

4 min read

663 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 P0303 cylinder 3 misfire in Toyota Corolla E170. Step-by-step guide with diagnostic procedures and repair instructions.

Error Code

P0303

Affected Component

Engine

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the negative battery terminal to prevent electrical shorts.
•Ensure the vehicle is parked on a flat surface and the engine is cool.

Symptoms

•Check engine light illuminated
•Rough idle or engine shaking
•Decreased fuel efficiency
•Engine stalling during acceleration
•Poor acceleration or power loss

Diagnostic Steps

1
Scan the vehicle’s computer using an OBD-II scanner to confirm the P0303 code and check for any additional trouble codes.
2
Inspect the ignition system components, including spark plugs and ignition coils, specifically for cylinder 3.
3
Check the fuel injectors for cylinder 3 for clogs or failures.
4
Perform a compression test on cylinder 3 to assess the health of the cylinder.
5
Inspect for vacuum leaks around the intake manifold and throttle body.
6
Examine the wiring and connectors associated with the ignition and fuel system for damage or corrosion.

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
•Spark plug socket
•Ratchet
•Screwdrivers
•Compression tester
•Fuel injector cleaner

Parts Required

•Ignition coil (if faulty)
•Spark plug (if worn)
•Fuel injector (if clogged or faulty)

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Scan the vehicle’s computer using an OBD-II scanner to confirm the P0303 code and check for any additional trouble codes.
2
Inspect the ignition system components, including spark plugs and ignition coils, specifically for cylinder 3.
3
Check the fuel injectors for cylinder 3 for clogs or failures.
4
Perform a compression test on cylinder 3 to assess the health of the cylinder.
5
Inspect for vacuum leaks around the intake manifold and throttle body.
6
Examine the wiring and connectors associated with the ignition and fuel system for damage or corrosion.

Solution

1. Preparation

Gather tools and parts required for the repair.
Ensure the vehicle is parked on a flat surface and the engine is cool.
Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Ignition Components

Tools Required: Socket set, Torque wrench, Spark plug socket, Ratchet, Screwdrivers
Remove the ignition coil from cylinder 3:
1. Disconnect the electrical connector from the ignition coil.
2. Unbolt the ignition coil using the socket set.
3. Remove the ignition coil and inspect it for cracks or wear.
Check the spark plug in cylinder 3:
1. Remove the spark plug using a spark plug socket.
2. Inspect the spark plug for wear, carbon buildup, or damage.
3. Replace the spark plug if necessary, ensuring to torque to manufacturer specifications (typically around 13-16 lb-ft).
Reinstall the ignition coil or replace it if faulty:
1. Position the ignition coil back onto the spark plug.
2. Tighten the bolts to manufacturer specifications (usually around 80-100 in-lbs).
3. Reconnect the electrical connector.

3. Check and Clean Fuel Injector

Tools Required: Fuel injector cleaner, Socket set
Remove the fuel injector for cylinder 3:
1. Depressurize the fuel system by removing the fuel pump fuse and running the engine until it stalls.
2. Remove the intake manifold or necessary components to access the fuel rail.
3. Disconnect the fuel line and electrical connector from the injector.
4. Unbolt and remove the injector.
Clean or replace the fuel injector:
1. Use a fuel injector cleaning kit to clean the injector.
2. If cleaning does not improve performance, replace with a new injector.
Reinstall the fuel injector:
1. Ensure O-rings are lubricated and seated properly.
2. Reconnect the fuel line and electrical connector.

4. Compression Test (If Needed)

Tools Required: Compression tester
Test the compression of cylinder 3:
1. Remove the spark plug from cylinder 3.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine for a few seconds and read the compression value.
If compression is below 130 psi, consider further diagnostics into the engine internals.