why does my Toyota Corolla E170 check engine light come on and off

Toyota Corolla E170 (2013-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

570 words

Problem Statement

Discover how to diagnose and fix the intermittent check engine light on your Toyota Corolla E170. Step-by-step guide with diagnostic and repair instructions.

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 inspecting or working on components.

Symptoms

•Check engine light illuminated intermittently
•Engine misfire or rough idle
•Decreased fuel efficiency
•Strange noises from the engine compartment
•Emission test failure
•Increased exhaust smoke

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify specific trouble codes.
2
Inspect the gas cap for proper sealing and condition; replace if damaged or loose.
3
Check for vacuum leaks in hoses and intake manifold using a smoke machine or visual inspection.
4
Test the ignition system components, including spark plugs and ignition coils, for wear or failure.
5
Examine the fuel system, including fuel pressure and injector operation, for irregularities.
6
Inspect the exhaust system for blockages or issues with the catalytic converter.

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
•Fuel pressure gauge
•Smoke machine

Parts Required

•Spark plugs
•Ignition coils
•Vacuum hoses
•Fuel filter

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify specific trouble codes.
2
Inspect the gas cap for proper sealing and condition; replace if damaged or loose.
3
Check for vacuum leaks in hoses and intake manifold using a smoke machine or visual inspection.
4
Test the ignition system components, including spark plugs and ignition coils, for wear or failure.
5
Examine the fuel system, including fuel pressure and injector operation, for irregularities.
6
Inspect the exhaust system for blockages or issues with the catalytic converter.

Solution

1. Preparation

Gather tools and parts required.
Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plugs

Remove the engine cover if necessary.
Use a spark plug socket to remove each spark plug.
Inspect the condition of the spark plugs for wear and deposits.
Replace with OEM-spec spark plugs if needed.
Torque the new spark plugs to the manufacturer’s specification (usually around 13-16 ft-lbs).

3. Check and Replace Ignition Coils

Remove the electrical connectors from each ignition coil.
Unbolt and remove the ignition coils from the engine.
Visually inspect for cracks or damage.
Replace any faulty ignition coils with new units.
Reinstall and torque bolts to specifications.

4. Inspect and Repair Vacuum Leaks

Start the engine and allow it to idle.
Use a smoke machine around the intake manifold and vacuum hoses to identify leaks.
If leaks are found, replace damaged hoses or gaskets.
Ensure all connections are secure and test again for leaks.

5. Fuel System Inspection

Use a fuel pressure gauge to check fuel pressure against specifications (typically 30-40 psi).
Inspect fuel injectors for proper operation. Clean or replace as necessary.
Replace the fuel filter if it hasn't been changed in a while.