AutoCodes – Toyota – P0118 2003 Toyota Highlander

P0118 2003 Toyota Highlander Code - Engine Coolant Temperature Circuit High Input

Quick Answer

The Engine Coolant Temperature (ECT) sensor is used to detect the engine coolant temperature. Common causes include Low engine coolant level, Faulty Engine Coolant Temperature (ECT) sensor, Faulty engine coolant thermostat. 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: P0118 2003 Toyota Highlander indicates Engine Coolant Temperature Circuit High Input.
Common causes: Common causes include Low engine coolant level, Faulty Engine Coolant Temperature (ECT) sensor, Faulty engine coolant thermostat.
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 4,603

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
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0118 2003 Toyota Highlander Description

The Engine Coolant Temperature (ECT) sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the Engine Control Module (ECM). The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.

OBDII Code P0118 2003 Toyota Highlander - Engine Coolant Temperature Circuit High Input - AutoCodes.com — P0118 2003 Toyota Highlander Code - Engine Coolant Temperature Circuit High Input

What does this mean?

What are the Possible Causes of the DTC P0118 2003 Toyota Highlander?

Low engine coolant level
Faulty Engine Coolant Temperature (ECT) sensor
Faulty engine coolant thermostat
Engine Coolant Temperature (ECT) sensor harness is open or shorted
Engine Coolant Temperature (ECT) sensor electrical circuit poor connection

How to Fix the DTC P0118 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 P0118 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 P0118 2003 Toyota Highlander code?

Need more information on how to fix the P0118 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 P0118 2003 Toyota Highlander Code

1. What are the common symptoms of OBDII code P0118 in a 2003 Toyota Highlander?

- Common symptoms include the engine running hot, temperature gauge reading high, check engine light illuminated, and potential decrease in fuel efficiency.

2. What does the OBDII code P0118 mean for a 2003 Toyota Highlander?

- OBDII code P0118 indicates that the Engine Coolant Temperature Circuit is registering a high input, potentially due to a faulty temperature sensor or wiring issue.

3. What are the possible causes of OBDII code P0118 in a 2003 Toyota Highlander?

- Possible causes include a malfunctioning engine coolant temperature sensor, damaged wiring or connections, low coolant levels, or a faulty thermostat.

4. How can I diagnose the issue causing OBDII code P0118 in my 2003 Toyota Highlander?

- To diagnose the issue, you can use a multimeter to test the engine coolant temperature sensor, visually inspect the wiring and connections for damage, and check the coolant level and thermostat.

5. Can OBDII code P0118 cause any long-term damage to my 2003 Toyota Highlander?

- If left unresolved, OBDII code P0118 can potentially cause engine overheating and damage, leading to more costly repairs in the long run.

6. How can I repair OBDII code P0118 in my 2003 Toyota Highlander?

- Repairing OBDII code P0118 may involve replacing the engine coolant temperature sensor, repairing or replacing damaged wiring, ensuring proper coolant levels, and checking the functionality of the thermostat.

7. Is it safe to continue driving my 2003 Toyota Highlander with OBDII code P0118 present?

- It is not recommended to continue driving with OBDII code P0118 present, as it can lead to engine overheating and potential damage.

8. Can a DIY enthusiast fix OBDII code P0118 in a 2003 Toyota Highlander?

- Depending on the skill level and experience, a DIY enthusiast may be able to diagnose and repair OBDII code P0118 by following repair guides and utilizing the necessary tools.

9. Will resetting the check engine light resolve OBDII code P0118 in my 2003 Toyota Highlander?

- Resetting the check engine light may temporarily clear the code, but it will not fix the underlying issue causing OBDII code P0118. It is important to diagnose and repair the root cause.

10. How much does it typically cost to repair OBDII code P0118 in a 2003 Toyota Highlander at a mechanic or dealership?

- The cost of repairing OBDII code P0118 can vary depending on the exact cause of the issue, but it may range from $100 to $300 for parts and labor at a mechanic or dealership.