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P0128 Mazda Code - Coolant Thermostat Malfunction

- Code Popularity: 58,505 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 2/3
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What are the Possible Causes of the DTC P0128 Mazda?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • 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
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How to Fix the DTC P0128 Mazda?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

There is a Factory Service Bulletin for the following Mazda models:

2004-2005 Mazda3 vehicles
2006-2007 Mazda5 vehicles
Mazda Factory Service Bulletin OBDII Code P0128

Search for P0128 Mazda Questions and Answers: Search here →

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0128 Mazda code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

When is the Code Detected?

The engine coolant temperature does not reach to specified temperature even though the engine has run long enough.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

Code P0128 Mazda Description

Indicates that the thermostat monitor has not achieved the required engine operating temperature within a specified amount of time after starting the engine.

OBDII Code P0128 Mazda - Coolant Thermostat Malfunction - AutoCodes.com
P0128 Mazda Code - Coolant Thermostat Malfunction

Need More Information on the Code?

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Code P0128 Mazda comments

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