AutoCodes – Toyota – P0356 2003 Toyota Highlander

P0356 2003 Toyota Highlander Code - Ignition Coil 6 Primary/Secondary Circuit

Quick Answer

The ignition system on the vehicle uses individual ignition coils for each cylinder. Common causes include Faulty Ignition Coil 6, Ignition Coil 6 harness is open or shorted, Ignition Coil 6 circuit poor electrical connection. 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: P0356 2003 Toyota Highlander indicates Ignition Coil 6 Primary/Secondary Circuit.
Common causes: Common causes include Faulty Ignition Coil 6, Ignition Coil 6 harness is open or shorted, Ignition Coil 6 circuit poor electrical connection.
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 3,158

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

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

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0356 2003 Toyota Highlander Description

The ignition system on the vehicle uses individual ignition coils for each cylinder. The Engine Control Module (ECM) controls each ignition coil operation. The ECM sends a ON/OFF signal to energize the ignition coil to create a spark at the spark plug when a spark is required at the cylinder.

OBDII Code P0356 2003 Toyota Highlander - Ignition Coil 6 Primary/Secondary Circuit - AutoCodes.com — P0356 2003 Toyota Highlander Code - Ignition Coil 6 Primary/Secondary Circuit

What does this mean?

What are the Possible Causes of the DTC P0356 2003 Toyota Highlander?

Faulty Ignition Coil 6
Ignition Coil 6 harness is open or shorted
Ignition Coil 6 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0356 2003 Toyota Highlander?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0356 2003 Toyota Highlander 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.

Need more information about the P0356 2003 Toyota Highlander code?

Need more information on how to fix the P0356 2003 Toyota Highlander code? Get Access to Factory Service Manuals

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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 P0356 2003 Toyota Highlander Code

1. What does OBDII code P0356 mean on a 2003 Toyota Highlander?

P0356 indicates an issue with the Ignition Coil 6 Primary/Secondary Circuit, meaning the ECM has detected a fault in the ignition coil or its circuit for cylinder 6.

2. What are the common symptoms of code P0356?

Symptoms include engine misfires, rough idling, poor fuel economy, reduced power, and the Check Engine Light being illuminated.

3. What causes code P0356 in a 2003 Toyota Highlander?

Common causes include a faulty ignition coil, damaged wiring or connectors, a bad ECM, or issues with the spark plug in cylinder 6.

4. How can I diagnose code P0356?

Start by inspecting the ignition coil, wiring, and connectors for damage. Swap the ignition coil with another cylinder to see if the code follows the coil. Use a multimeter to check for continuity and proper voltage.

5. Can I drive my 2003 Toyota Highlander with code P0356?

While driving may be possible, it is not recommended. Continued driving can cause engine damage, increased emissions, and unsafe operation due to misfires.

6. How do I fix code P0356?

Potential fixes include replacing the ignition coil for cylinder 6, repairing damaged wiring or connectors, replacing the spark plug, or addressing ECM issues if necessary.

7. How much does it cost to repair code P0356?

Typical costs range from $50 to $150 for an ignition coil and $100 to $200 for professional labor. Additional repairs such as wiring fixes may increase the cost.

8. Can a bad spark plug cause code P0356?

Yes, a worn or damaged spark plug in cylinder 6 can cause ignition coil issues, triggering code P0356.

9. Will clearing the code fix the problem?

Clearing the code will turn off the Check Engine Light temporarily, but the underlying problem must be resolved to prevent the code from returning.

10. Is code P0356 a common issue in the 2003 Toyota Highlander?

Itâ€™s not particularly common but can occur as components like ignition coils and spark plugs wear out over time. Regular maintenance can help prevent it.