AutoCodes – Subaru – P1490 Subaru

P1490 Subaru Code - Thermostat Malfunction

Quick Answer

P1490 Subaru indicates Thermostat Malfunction. Common causes include Faulty Thermostat, Faulty Engine Coolant Blower Motor, Engine Coolant Blower Motor harness is open or shorted. 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: P1490 Subaru indicates Thermostat Malfunction.
Common causes: Common causes include Faulty Thermostat, Faulty Engine Coolant Blower Motor, Engine Coolant Blower Motor harness is open or shorted.
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 7,558

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Aug 24, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1490 Subaru Description

OBDII Code P1490 Subaru - Thermostat Malfunction - AutoCodes.com — P1490 Subaru Code - Thermostat Malfunction

What does this mean?

What are the Possible Causes of the DTC P1490 Subaru?

Faulty Thermostat
Faulty Engine Coolant Blower Motor
Engine Coolant Blower Motor harness is open or shorted
Engine Coolant Blower Motor electrical circuit poor connection

How to Fix the DTC P1490 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 P1490 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 P1490 Subaru code?

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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 P1490 Subaru Code

1. What does the OBDII code P1490 mean in a Subaru?

P1490 on a Subaru indicates a "Thermostat Malfunction," meaning the engine's cooling system is not maintaining proper temperature due to an issue with the thermostat.

2. What are the common symptoms of code P1490 in a Subaru?

Symptoms may include an illuminated check engine light, fluctuating engine temperatures, poor heater performance, or the engine running too cold or hot.

3. What causes the P1490 code to appear in a Subaru?

Common causes include a stuck-open or stuck-closed thermostat, a failing thermostat sensor, low coolant levels, or wiring and electrical issues related to the thermostat.

4. Can I drive my Subaru with a P1490 code?

Driving with this code is not recommended, as an improperly functioning thermostat can lead to engine overheating or inefficient operation, potentially causing long-term damage.

5. How do I diagnose the P1490 code on a Subaru?

Start by visually inspecting the thermostat, checking for stuck positions or leaks. Verify proper coolant levels, and use a scan tool to monitor temperature sensor readings.

6. What is the most common fix for the P1490 code in a Subaru?

The most common fix is replacing a faulty thermostat. Ensuring the new thermostat meets OEM specifications is crucial for proper operation.

7. Can low coolant levels trigger the P1490 code on a Subaru?

Yes, low coolant levels can affect the thermostat's operation and trigger the code. Always check and top off coolant to the proper level.

8. Is the P1490 code related to the engine temperature sensor in a Subaru?

While the code primarily refers to the thermostat, a malfunctioning engine temperature sensor can also contribute by providing incorrect readings.

9. How much does it cost to fix the P1490 code on a Subaru?

Repair costs can range from $50 to $250, depending on whether you replace a thermostat or address additional issues like coolant leaks or sensor problems.

10. Can a faulty thermostat affect fuel efficiency in a Subaru?

Yes, a malfunctioning thermostat can cause the engine to run too cold or too hot, reducing fuel efficiency and overall performance.