AutoCodes – Toyota – P1118 2005 Toyota Prius

P1118 2005 Toyota Prius Code - Coolant Temperature Sensor Circuit High for Coolant Heat Storage System

Quick Answer

This system uses an electric pump to supply hot coolant stored in the coolant 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 Heat Storage Tank, Faulty Engine Coolant Temperature (ECT) sensor for CHS (Coolant Heat Storage), Low engine coolant level. 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
P1118 2005 Toyota Prius indicates Coolant Temperature Sensor Circuit High for Coolant Heat Storage System.
Common causes
Common causes include Coolant Heat Storage Tank, Faulty Engine Coolant Temperature (ECT) sensor for CHS (Coolant Heat Storage), Low engine coolant level.
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 7,806
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Apr 24, 2019
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Code P1118 2005 Toyota Prius Description

This system uses an electric pump to supply hot coolant stored in the coolant 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 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
OBDII Code P1118 2005 Toyota Prius - Coolant Temperature Sensor Circuit High for Coolant Heat Storage System - AutoCodes.com
P1118 2005 Toyota Prius Code - Coolant Temperature Sensor Circuit High for Coolant Heat Storage System

What are the Possible Causes of the DTC P1118 2005 Toyota Prius?

  • Coolant Heat Storage Tank
  • Faulty Engine Coolant Temperature (ECT) sensor for CHS (Coolant Heat Storage)
  • Low engine coolant level
  • Engine Coolant Temperature (ECT) sensor for HST harness is open or shorted
  • Engine Coolant Temperature (ECT) sensor for HST electrical circuit poor connection
  • Faulty engine coolant thermostat

How to Fix the DTC P1118 2005 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 P1118 2005 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 P1118 2005 Toyota Prius code?

Need more information on how to fix the P1118 2005 Toyota Prius code? Get Access to Factory Service Manuals

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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 P1118 2005 Toyota Prius Code

1. What are the common symptoms of OBDII code P1118 in a 2005 Toyota Prius?

The common symptoms include the engine running hotter than normal, the temperature gauge reading high, and the Check Engine light illuminating on the dashboard.

2. What does the OBDII code P1118 indicate for a 2005 Toyota Prius?

The code P1118 indicates a problem with the Coolant Temperature Sensor Circuit High for the Coolant Heat Storage System in the Prius.

3. What are the possible causes of OBDII code P1118 in a 2005 Toyota Prius?

Possible causes include a faulty coolant temperature sensor, a short or open circuit in the sensor wiring, or issues with the sensor connector.

4. How can I diagnose the OBDII code P1118 in my 2005 Toyota Prius?

Diagnosing the code may involve checking the coolant temperature sensor's resistance, inspecting the sensor wiring for damage, and scanning for any other related trouble codes.

5. Can I continue driving my 2005 Toyota Prius with OBDII code P1118?

It is not recommended to drive the vehicle with code P1118 as it can lead to overheating issues and potential engine damage. It is best to address the problem promptly.

6. How can I repair OBDII code P1118 in my 2005 Toyota Prius?

Repairing the code may involve replacing the coolant temperature sensor, repairing any damaged wiring, or addressing any other underlying issues causing the high circuit reading.

7. Is it possible to reset the OBDII code P1118 in a 2005 Toyota Prius?

Resetting the code can be done using an OBDII scanner or by disconnecting the car battery for a few minutes. However, it is important to address the root cause of the issue to prevent the code from recurring.

8. How much does it typically cost to repair OBDII code P1118 in a 2005 Toyota Prius?

The cost of repairing code P1118 can vary depending on the specific cause of the issue, the labor rates in your area, and whether you choose to do the repairs yourself or take it to a professional mechanic.

9. Can a DIY enthusiast fix OBDII code P1118 in a 2005 Toyota Prius?

Depending on your skill level and access to tools, some DIY enthusiasts may be able to diagnose and repair code P1118. However, if you are unsure, it is recommended to seek the help of a professional mechanic.

10. How often does OBDII code P1118 occur in a 2005 Toyota Prius?

Code P1118 related to the Coolant Temperature Sensor Circuit High for the Coolant Heat Storage System may occur occasionally in a 2005 Toyota Prius, especially as the vehicle ages and the sensor components wear out.

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