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P0128 Mitsubishi Code - Coolant Thermostat Malfunction

- Code Popularity: 26,780 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 2/3
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What are the Possible Causes of the DTC P0128 Mitsubishi?

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 Mitsubishi?

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

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

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0128 Mitsubishi 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 Mitsubishi 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 Mitsubishi - Coolant Thermostat Malfunction - AutoCodes.com
P0128 Mitsubishi Code - Coolant Thermostat Malfunction

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