AutoCodes – Toyota – P0128 2017 Toyota RAV4

P0128 2017 Toyota RAV4 Code - Coolant Thermostat

Quick Answer

The ECM estimates the engine coolant temperature based on the starting temperature, engine loads, and engine speeds. Common causes include Leaking or stuck open thermostat, Low engine coolant level, Insufficient warm up time. 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: P0128 2017 Toyota RAV4 indicates Coolant Thermostat.
Common causes: Common causes include Leaking or stuck open thermostat, Low engine coolant level, Insufficient warm up time.
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 511

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 Aug 23, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P0128 2017 Toyota RAV4 Description

The ECM estimates the engine coolant temperature based on the starting temperature, engine loads, and engine speeds. The Engine Control Module (ECM) then compares the estimated temperature with the actual engine coolant temperature. When the estimated engine coolant temperature reaches 75°C (167°F), the ECM checks the actual engine coolant temperature. If the actual engine coolant temperature is less than 75°C (167°F), the ECM interprets this as a malfunction in the thermostat or the engine cooling system and stores the Diagnostic Trouble Code (DTC).

OBDII Code P0128 2017 Toyota RAV4 - Coolant Thermostat - AutoCodes.com — P0128 2017 Toyota RAV4 Code - Coolant Thermostat

What does this mean?

What are the Possible Causes of the DTC P0128 2017 Toyota RAV4?

Leaking or stuck open thermostat
Low engine coolant level
Insufficient warm up time
Faulty Engine Coolant Temperature (ECT) sensor
Engine Coolant Temperature sensor harness is open or shorted
Engine Coolant Temperature sensor electrical circuit poor connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0128 2017 Toyota RAV4?

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 does this mean?

Code Tech Notes

If the cooling system is not leaking and the fluid level is OK, replacing the thermostat usually takes care of the problem.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0128 2017 Toyota RAV4 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.

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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 P0128 2017 Toyota RAV4 Code

1. What does OBDII code P0128 in a 2017 Toyota RAV4 indicate?

The P0128 code in a 2017 Toyota RAV4 typically indicates a problem with the coolant thermostat.

2. What are the common symptoms of a P0128 code in a 2017 Toyota RAV4?

Common symptoms include the engine running colder than normal, poor fuel economy, and potentially a lack of heat from the vehicle's heater.

3. What are the possible causes of a P0128 code in a 2017 Toyota RAV4?

Potential causes include a faulty thermostat, a malfunctioning engine coolant temperature sensor, low coolant levels, or issues with the engine cooling system.

4. How serious is a P0128 code in a 2017 Toyota RAV4?

While the issue may not cause immediate harm to the vehicle, it can lead to reduced fuel efficiency, poor performance, and potential long-term damage if left unresolved.

5. Can I continue driving my 2017 Toyota RAV4 with a P0128 code?

It is generally not recommended to continue driving with a P0128 code as it can lead to decreased fuel efficiency and potential engine overheating issues.

6. How can I repair a P0128 code in my 2017 Toyota RAV4?

Repairing a P0128 code typically involves replacing the thermostat, checking and topping up coolant levels, and ensuring the cooling system is functioning properly.

7. How much does it cost to fix a P0128 code in a 2017 Toyota RAV4?

The cost of fixing a P0128 code can vary depending on the underlying cause, but it may range from around $150 to $400 or more, including parts and labor.

8. Can a P0128 code be triggered by a temporary issue?

Yes, sometimes a P0128 code can be triggered by a temporary glitch or a one-time event. However, it's important to diagnose the issue to prevent any potential long-term problems.

9. How can I prevent a P0128 code from appearing in my 2017 Toyota RAV4?

Regular maintenance, such as checking coolant levels, replacing the thermostat as recommended, and addressing any cooling system issues promptly, can help prevent the recurrence of a P0128 code.

10. Will resetting the OBDII system clear a P0128 code in a 2017 Toyota RAV4?

While resetting the system may temporarily clear the code, it is crucial to address the underlying issue causing the P0128 code to prevent it from reappearing.