AutoCodes – Nissan – P0128 2009 Nissan Pathfinder

P0128 2009 Nissan Pathfinder Code - Thermostat Function

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 2009 Nissan Pathfinder indicates Thermostat Function.
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 3,449

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 2009 Nissan Pathfinder 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 2009 Nissan Pathfinder - Thermostat Function - AutoCodes.com — P0128 2009 Nissan Pathfinder Code - Thermostat Function

What does this mean?

What are the Possible Causes of the DTC P0128 2009 Nissan Pathfinder?

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 2009 Nissan Pathfinder?

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 2009 Nissan Pathfinder 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 2009 Nissan Pathfinder Code

1. What does OBDII code P0128 on a 2009 Nissan Pathfinder indicate?

- This code typically indicates an issue with the thermostat function in the engine coolant system.

2. What are the common symptoms of a P0128 code in a 2009 Nissan Pathfinder?

- Common symptoms include the engine running hotter or colder than normal, decreased fuel efficiency, and a potential check engine light.

3. What are the possible causes of a P0128 code in a 2009 Nissan Pathfinder?

- The code may be triggered by a faulty thermostat, low coolant levels, a malfunctioning coolant temperature sensor, or a problem with the cooling system.

4. How can I diagnose the cause of a P0128 code in my 2009 Nissan Pathfinder?

- Diagnosis typically involves checking the coolant level, inspecting the thermostat for proper operation, testing the coolant temperature sensor, and ensuring the cooling system is functioning correctly.

5. Can a P0128 code be triggered by a faulty thermostat in a 2009 Nissan Pathfinder?

- Yes, a malfunctioning thermostat is a common cause of the P0128 code as it can lead to improper regulation of the engine temperature.

6. What are some repair tips for addressing a P0128 code in a 2009 Nissan Pathfinder?

- It is advisable to start by checking and replacing the thermostat if necessary, ensuring the cooling system is properly filled with coolant, and inspecting the coolant temperature sensor for any issues.

7. Is it safe to continue driving with a P0128 code on a 2009 Nissan Pathfinder?

- It is not recommended to ignore the P0128 code as it can lead to potential engine overheating issues and further damage if left unresolved.

8. Can a P0128 code be reset in a 2009 Nissan Pathfinder without addressing the underlying issue?

- While resetting the code may temporarily turn off the check engine light, it is important to diagnose and repair the root cause to prevent future problems.

9. How much does it typically cost to repair a P0128 code in a 2009 Nissan Pathfinder?

- The cost of repair can vary depending on the specific cause, but it may involve expenses for parts like a new thermostat, coolant, or coolant temperature sensor, as well as labor costs for installation.

10. What is the function of the thermostat in the cooling system of a 2009 Nissan Pathfinder?

- The thermostat regulates the flow of coolant through the engine to maintain optimal operating temperature, ensuring efficient performance and preventing overheating.