AutoCodes – Scion – P0128 2007 Scion xB

P0128 2007 Scion xB Code - Coolant Thermostat

Quick Answer

The thermostat is a component that blocks the flow of coolant to the radiator until the engine has warmed up. 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 2007 Scion xB 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 3,839

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 Apr 21, 2019

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0128 2007 Scion xB Description

The thermostat is a component that blocks the flow of coolant to the radiator until the engine has warmed up. When the engine is cold, no coolant flows through the engine. Once the engine reaches its operating temperature, the thermostat opens. The OBDII sets when the engine coolant temperature has not risen enough to open the thermostat even though the engine has run long enough. This is due to a leak in the seal or the thermostat open stuck.

OBDII Code P0128 2007 Scion xB - Coolant Thermostat - AutoCodes.com — P0128 2007 Scion xB Code - Coolant Thermostat

What does this mean?

What are the Possible Causes of the DTC P0128 2007 Scion xB?

Leaking or stuck open thermostat
Low engine coolant level
Insufficient warm up time
Faulty engine coolant temperature sensor
Engine coolant temperature sensor harness is open or shorted
Engine coolant temperature sensor circuit poor electrical connection

How to Fix the DTC P0128 2007 Scion xB?

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

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0128 2007 Scion xB 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 2007 Scion xB Code

1. What does OBDII code P0128 on a 2007 Scion xB indicate?

This code typically points to an issue with the coolant thermostat in the vehicle.

2. What are the common symptoms of a P0128 code in a 2007 Scion xB?

Common symptoms include the engine running cooler than normal, poor fuel economy, and the check engine light being illuminated.

3. What are the possible causes of a P0128 code in a 2007 Scion xB?

The most common causes are a faulty coolant thermostat, low coolant levels, a malfunctioning coolant temperature sensor, or a problem with the engine's cooling system.

4. How can I diagnose the issue causing a P0128 code in my 2007 Scion xB?

To diagnose the problem, you can start by checking the coolant level, inspecting the thermostat for proper operation, and testing the coolant temperature sensor using a multimeter.

5. Can I continue driving my 2007 Scion xB with a P0128 code?

It is not recommended to continue driving with a P0128 code as it can lead to poor engine performance and potential overheating issues.

6. How do I repair a P0128 code on my 2007 Scion xB?

The most common fix is to replace the coolant thermostat with a new one. It's also a good idea to flush the cooling system and ensure all components are working correctly.

7. Are there any DIY tips for fixing a P0128 code in a 2007 Scion xB?

If you're comfortable with basic car repairs, you can attempt to replace the thermostat yourself using a repair manual or online guides. Just make sure to follow proper safety precautions.

8. How much does it cost to repair a P0128 code on a 2007 Scion xB?

The cost of repairing a P0128 code can vary depending on the root cause of the issue and whether you're doing the repair yourself or taking it to a mechanic. Generally, replacing the thermostat can cost anywhere from $100 to $300.

9. Can a P0128 code be triggered by something other than the coolant thermostat in a 2007 Scion xB?

While the thermostat is the most common culprit, other factors like a faulty coolant temperature sensor or a cooling system leak can also trigger a P0128 code.

10. How often should the coolant thermostat be replaced in a 2007 Scion xB?

The coolant thermostat should be inspected regularly and replaced as needed, typically every 50,000 to 100,000 miles or if any issues arise with the engine's cooling system.