AutoCodes – Toyota – P1120 2009 Toyota Prius

P1120 2009 Toyota Prius Code - Coolant Flow Control Valve Position Sensor Circuit

Quick Answer

This system uses an electric pump to supply hot coolant stored in the heat storage tank into the cylinder head of the engine, in order to optimize engine starting combustion and reduce the amount of unburned gas that is discharged while the engine is started. Common causes include Coolant Flow Control Valve, Faulty Coolant Flow Control Valve Position Sensor, Coolant Flow Control Valve Position Sensor harness is open or shorted. 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: P1120 2009 Toyota Prius indicates Coolant Flow Control Valve Position Sensor Circuit.
Common causes: Common causes include Coolant Flow Control Valve, Faulty Coolant Flow Control Valve Position Sensor, Coolant Flow Control Valve Position Sensor harness is open or shorted.
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 3,442

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 12, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1120 2009 Toyota Prius Description

This system uses an electric pump to supply hot coolant stored in the heat storage tank into the cylinder head of the engine, in order to optimize engine starting combustion and reduce the amount of unburned gas that is discharged while the engine is started. Before the engine starts, the Engine Control Module (ECM) operates the electric water pump to direct the hot coolant in the heat storage tank into the engine, in order to heat the cylinder head (this process is called preheat mode). The duration of the operation of the electric water pump is variable, depending on the temperature of the cylinder head. During the normal operation of the engine, the water valve opens the passage between the cylinder head and the heater and closes the passage between the cylinder head and the tank. During preheat mode in which the cylinder head is heated, the water valve opens the passage between the tank and the cylinder head, in order to allow the coolant to flow from the tank to the cylinder head. At this time, in order to warm up the intake port quickly before the engine is started, the coolant flows in the reverse direction.
The water valve for the Coolant Heat Storage (CHS) system, which is located at the heater hoses, controls the coolant passages to the engine, heater core, and the CHS tank in accordance with the operating conditions of the system.
The water valve consists of a water valve, valve position sensor, and valve control motor. The potentiometer, which is coupled coaxially to the water valve, converts the valve position into voltage and transmits it to the ECM in the form of a position signal.

OBDII Code P1120 2009 Toyota Prius - Coolant Flow Control Valve Position Sensor Circuit - AutoCodes.com — P1120 2009 Toyota Prius Code - Coolant Flow Control Valve Position Sensor Circuit

What does this mean?

What are the Possible Causes of the DTC P1120 2009 Toyota Prius?

Coolant Flow Control Valve
Faulty Coolant Flow Control Valve Position Sensor
Coolant Flow Control Valve Position Sensor harness is open or shorted
Coolant Flow Control Valve Position Sensor circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P1120 2009 Toyota Prius?

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 P1120 2009 Toyota Prius 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.

Need more information about the P1120 2009 Toyota Prius code?

Need more information on how to fix the P1120 2009 Toyota Prius code? Get Access to Factory Service Manuals

Need Help with the Code?

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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.

Frequently Asked Questions about P1120 2009 Toyota Prius Code

1. What does OBDII code P1120 on a 2009 Toyota Prius mean?

Code P1120 indicates a problem with the Coolant Flow Control Valve Position Sensor Circuit in the vehicle.

2. What are some common symptoms of a Coolant Flow Control Valve Position Sensor Circuit issue?

Common symptoms include engine overheating, poor fuel economy, rough idle, and a check engine light illuminated on the dashboard.

3. What are the possible causes of OBDII code P1120 on a 2009 Toyota Prius?

Potential causes may include a faulty coolant flow control valve, a malfunctioning position sensor, wiring issues, or a problem with the engine control module.

4. How can I diagnose a Coolant Flow Control Valve Position Sensor Circuit problem in my 2009 Toyota Prius?

Diagnosis typically involves using an OBDII scanner to retrieve the specific trouble code, inspecting the coolant flow control valve and sensor for proper operation, and checking the wiring connections for any damage.

5. Can I continue driving my 2009 Toyota Prius with OBDII code P1120 present?

It is not recommended to drive your vehicle with code P1120 as it can lead to engine damage or other issues. It's best to address the problem promptly.

6. How can I repair OBDII code P1120 on my 2009 Toyota Prius?

Repair options may include replacing the coolant flow control valve, replacing the position sensor, repairing any damaged wiring, or resetting the engine control module after fixing the issue.

7. Is it possible to reset the check engine light after fixing OBDII code P1120 on a 2009 Toyota Prius?

Yes, the check engine light can be reset using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes.

8. Are there any preventive maintenance tips to avoid OBDII code P1120 on a 2009 Toyota Prius?

Regularly servicing your vehicle, checking coolant levels, monitoring engine temperature, and addressing any cooling system issues promptly can help prevent code P1120 from occurring.

9. Can a DIY enthusiast with basic automotive knowledge fix OBDII code P1120 on a 2009 Toyota Prius?

Depending on the specific issue causing code P1120, some repairs may be within reach for a DIY enthusiast. However, complex electrical or sensor-related problems may require professional assistance.

10. How much can I expect to pay for repairing OBDII code P1120 on a 2009 Toyota Prius?

The cost of repairing code P1120 can vary widely depending on the exact cause of the issue, parts needed for replacement, and labor costs. It's advisable to obtain quotes from different mechanics or service centers for an accurate estimate.

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