AutoCodes – Subaru – P0126 Subaru

P0126 Subaru Code - Insufficient Coolant Temperature for Stable Operation

Quick Answer

The Engine Coolant Temperature (ECT) sensor is used to detect the engine coolant temperature. Common causes include Low engine coolant level, Leaking or stuck open thermostat, Faulty Engine Coolant Temperature (ECT) sensor. 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: P0126 Subaru indicates Insufficient Coolant Temperature for Stable Operation.
Common causes: Common causes include Low engine coolant level, Leaking or stuck open thermostat, Faulty Engine Coolant Temperature (ECT) sensor.
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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 7,440

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0126 Subaru 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 P0126 Subaru - Insufficient Coolant Temperature for Stable Operation - AutoCodes.com — P0126 Subaru Code - Insufficient Coolant Temperature for Stable Operation

What does this mean?

What are the Possible Causes of the DTC P0126 Subaru?

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

How to Fix the DTC P0126 Subaru?

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 P0126 Subaru 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 P0126 Subaru code?

Need more information on how to fix the P0126 Subaru code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0126 Subaru code diagnosed by a professional: Find a repair shop in your area

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 P0126 Subaru Code

1. What are the common symptoms of OBDII code P0126 in a Subaru?

- Common symptoms include a check engine light, engine overheating, poor fuel economy, and a decrease in engine performance.

2. What does the OBDII code P0126 in a Subaru indicate?

- The code indicates that the engine coolant temperature is not reaching the proper operating temperature within a specified time period.

3. What are the possible causes of OBDII code P0126 in a Subaru?

- Possible causes include a faulty thermostat, low engine coolant level, a malfunctioning coolant temperature sensor, or issues with the cooling system.

4. How can I diagnose the cause of OBDII code P0126 in my Subaru?

- A diagnostic scan tool can be used to read the code and check live data to monitor the engine coolant temperature sensor readings and confirm if the thermostat is functioning correctly.

5. Can I continue driving my Subaru with OBDII code P0126?

- It is not recommended to drive the vehicle with this code active as it can lead to engine overheating, potential damage, and reduced fuel efficiency.

6. How can I repair OBDII code P0126 in my Subaru?

- Repair options may include replacing the thermostat, topping up the engine coolant, testing and replacing the coolant temperature sensor, or addressing any cooling system issues.

7. Are there any simple tips to prevent OBDII code P0126 in my Subaru?

- Regularly checking and maintaining the coolant level, ensuring the thermostat is functioning properly, and addressing any signs of overheating promptly can help prevent this code.

8. How long does it typically take to repair OBDII code P0126 in a Subaru?

- The repair time can vary depending on the exact cause of the code, but it may take anywhere from 1 to 3 hours to diagnose and fix the issue.

9. Could a dirty air filter cause OBDII code P0126 in a Subaru?

- While a dirty air filter can impact engine performance, it is not directly related to the coolant temperature issue indicated by OBDII code P0126.

10. Is it necessary to reset the OBDII code P0126 after repairing the issue in a Subaru?

- Yes, it is recommended to clear the code using a diagnostic scan tool after repairing the underlying problem to reset the check engine light and monitor for any recurring issues.