Coolant Thermostat Malfunction
Table of contents
- Possible Causes
- How To Fix
- Tech Notes
- Cost To Diagnose
- When is the code detected
- Possible Symptoms
- Description
P0128 MAZDA Possible 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
How do I fix code P0128 MAZDA?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
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
Cost of diagnosing the P0128 MAZDA code
The cost of diagnosing the P0128 MAZDA code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops 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.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
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.