AutoCodes – Scion – P0125 Scion

P0125 Scion Code - Insufficient Coolant Temperature for Closed Loop Fuel Control

Quick Answer

The resistance of the engine coolant temperature sensor varies in proportion to the actual engine coolant temperature. Common causes include Low engine coolant level, Leaking or stuck open thermostat, Faulty Engine Coolant Temperature (ECT) sensor. 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: P0125 Scion indicates Insufficient Coolant Temperature for Closed Loop Fuel Control.
Common causes: Common causes include Low engine coolant level, Leaking or stuck open thermostat, Faulty Engine Coolant Temperature (ECT) sensor.
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 5,101

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 Aug 23, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0125 Scion Description

The resistance of the engine coolant temperature sensor varies in proportion to the actual engine coolant temperature. The Engine Control Module (ECM)supplies a constant voltage to the sensor and monitors the signal output voltage of the sensor. The signal output voltage varies according to the changing resistance of the sensor. After the engine is started, the engine coolant temperature is monitored by this signal. If the engine coolant temperature sensor indicates that the engine is not yet warm enough for closed-loop fuel control, despite a specified period of time has elapsed since the engine was started, the ECM interprets this as a malfunction in the sensor or cooling system and stores the Diagnostic Trouble Code (DTC).

OBDII Code P0125 Scion - Insufficient Coolant Temperature for Closed Loop Fuel Control - AutoCodes.com — P0125 Scion Code - Insufficient Coolant Temperature for Closed Loop Fuel Control

What does this mean?

What are the Possible Causes of the DTC P0125 Scion?

Low engine coolant level
Leaking or stuck open thermostat
Faulty Engine Coolant Temperature (ECT) sensor
Engine Coolant Temperature sensor harness is open or shorted
Engine Coolant Temperature sensor electrical circuit poor connection

How to Fix the DTC P0125 Scion?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0125 Scion 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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Information for Specific Scion Models

P0125 2005 Scion xB — Insufficient Coolant Temperature for Closed Loop Fuel Control
P0125 2006 Scion xB — Insufficient Coolant Temperature for Closed Loop Fuel Control
P0125 2007 Scion xB — Insufficient Coolant Temperature for Closed Loop Fuel Control

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.