How much does a thermostat replacement cost?

A thermostat replacement typically costs $150-$400 including parts and labor. It is one of the more affordable cooling system repairs and can resolve many temperature-related codes.

Why does my car keep overheating?

Common causes include a stuck thermostat, low coolant from leaks, a failed water pump, a clogged radiator, or malfunctioning cooling fans. A proper diagnosis is needed to identify the specific cause.

P0115

Engine Coolant Temperature Circuit Malfunction

Moderatecooling

Overview

The P0115 diagnostic trouble code indicates a engine coolant temperature circuit malfunction condition. This code relates to the engine cooling system, which maintains proper operating temperature for the engine. Cooling system problems can lead to overheating and serious engine damage if not addressed in a timely manner.

Symptoms

Temperature gauge reading high
Poor heater performance
Coolant leak
Check Engine Light (MIL) illuminated

Common Causes

Failed radiator cap
Faulty engine coolant temperature sensor
Malfunctioning cooling fan or relay
Faulty thermostat (stuck open or closed)

Diagnosis Steps

1Connect an OBD-II scanner and read all stored trouble codes and freeze frame data
2Check coolant level and inspect for visible leaks
3Test the thermostat by monitoring coolant temperature during warm-up
4Inspect the coolant temperature sensor and its wiring
5Test the cooling fan operation by running the AC or using a scan tool

Estimated Repair Cost

$100 — $800

Cost varies by vehicle, location, and repair shop. Includes parts and labor.

Commonly Affected Vehicles

Nissan MuranoAudi Q5BMW 3 SeriesFord Taurus

Related Codes

P0118 P0217 P0117

More Cooling Codes

P0116Engine Coolant Temperature Circuit Range/Performance

Moderate

P0117Engine Coolant Temperature Circuit Low Input

Moderate

P0118Engine Coolant Temperature Circuit High Input

Moderate

P0119Engine Coolant Temperature Circuit Intermittent

Moderate

P0125Insufficient Coolant Temperature for Closed Loop Fuel Control

Moderate

P0126Insufficient Coolant Temperature for Stable Operation

Moderate

Frequently Asked Questions

If your engine is overheating, stop driving immediately to prevent catastrophic engine damage. If the code is related to a sensor or thermostat and the temperature is stable, drive cautiously to a repair shop.