AutoCodes – Toyota – P0354 2004 Toyota Highlander

P0354 2004 Toyota Highlander Code - Ignition Coil 4 Primary/Secondary Circuit

Quick Answer

The ignition system on the vehicle uses individual ignition coils for each cylinder. Common causes include Faulty Ignition Coil 4, Ignition Coil 4 harness is open or shorted, Ignition Coil 4 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: P0354 2004 Toyota Highlander indicates Ignition Coil 4 Primary/Secondary Circuit.
Common causes: Common causes include Faulty Ignition Coil 4, Ignition Coil 4 harness is open or shorted, Ignition Coil 4 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 6,176

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 Mar 29, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0354 2004 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 P0354 2004 Toyota Highlander - Ignition Coil 4 Primary/Secondary Circuit - AutoCodes.com — P0354 2004 Toyota Highlander Code - Ignition Coil 4 Primary/Secondary Circuit

What does this mean?

What are the Possible Causes of the DTC P0354 2004 Toyota Highlander?

Faulty Ignition Coil 4
Ignition Coil 4 harness is open or shorted
Ignition Coil 4 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0354 2004 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 P0354 2004 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 P0354 2004 Toyota Highlander code?

Need more information on how to fix the P0354 2004 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 P0354 2004 Toyota Highlander Code

1. What does the OBDII code P0354 mean on a 2004 Toyota Highlander?

P0354 indicates a malfunction in the Ignition Coil 4 Primary/Secondary Circuit, meaning the engine control module (ECM) has detected an issue with the ignition coil on cylinder 4.

2. What are the common symptoms of a P0354 code?

Symptoms include engine misfires, rough idling, reduced fuel efficiency, hesitation during acceleration, and the check engine light turning on.

3. What causes the P0354 code on a Toyota Highlander?

Common causes include a faulty ignition coil, damaged wiring or connectors in the coil's circuit, a defective ECM, or a bad spark plug on cylinder 4.

4. How do I locate ignition coil 4 on a 2004 Toyota Highlander?

On the 2004 Toyota Highlander, the ignition coils are typically numbered in the firing order. Refer to the vehicle's cylinder layout diagram to identify cylinder 4.

5. Can a bad spark plug cause a P0354 code?

Yes, a worn or damaged spark plug on cylinder 4 can cause ignition coil issues, leading to the P0354 code.

6. How can I troubleshoot the P0354 code?

Inspect ignition coil 4 for damage, check the wiring and connectors for corrosion or loose connections, and test the coil with a multimeter. Replacing the spark plug may also help.

7. Can I drive my 2004 Toyota Highlander with a P0354 code?

Driving with a P0354 code is not recommended, as it can lead to engine misfires, reduced performance, and potential damage to the catalytic converter.

8. How much does it cost to fix a P0354 code?

Repair costs vary but typically range from $100 to $300, depending on whether the ignition coil, spark plug, or wiring needs replacement.

9. Can a P0354 code clear itself?

The code may clear temporarily if the issue is intermittent, but the problem needs to be resolved to prevent further damage and ensure proper engine performance.

10. Is it necessary to replace all ignition coils if P0354 appears?

No, only the faulty ignition coil (cylinder 4) needs replacement. However, if other coils are aging, replacing them as a set may be beneficial for long-term reliability.