AutoCodes – Toyota – P0657 2008 Toyota Prius

P0657 2008 Toyota Prius Code - Actuator Supply Voltage Circuit Open

Quick Answer

The Engine Control Module (ECM) continuously monitors its internal memory status, internal circuits, and output signals to the throttle actuator. Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine Control Module circuit poor electrical connection. 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: P0657 2008 Toyota Prius indicates Actuator Supply Voltage Circuit Open.
Common causes: Common causes include Faulty Engine Control Module (ECM), Engine Control Module harness is open or shorted, Engine Control Module circuit poor electrical connection.
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 1,812

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 Jan 25, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0657 2008 Toyota Prius Description

The Engine Control Module (ECM) continuously monitors its internal memory status, internal circuits, and output signals to the throttle actuator. This self−check insures that the ECM is functioning properly. If any malfunction is detected, the ECM will set the code and illuminate the engine light.
The ECM memory status is diagnosed by internal mirroring of the main CPU and the sub CPU to detect Random Access Memory (RAM) errors. The two CPUs also perform continuous mutual monitoring. The ECM illuminates the MIL and sets a DTC if: 1) outputs from the two CPUs are different or deviate from the standards, 2) the signals sent to the throttle actuator deviate from the standards, 3) a malfunction is found in the throttle actuator supply voltage, and 4) any other ECM malfunction is found.

OBDII Code P0657 2008 Toyota Prius - Actuator Supply Voltage Circuit Open - AutoCodes.com — P0657 2008 Toyota Prius Code - Actuator Supply Voltage Circuit Open

What does this mean?

What are the Possible Causes of the DTC P0657 2008 Toyota Prius?

Faulty Engine Control Module (ECM)
Engine Control Module harness is open or shorted
Engine Control Module circuit poor electrical connection
Engine Control Module Programming update

How to Fix the DTC P0657 2008 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 does this mean?

Code Tech Notes

Check the ECM fuse, if fuse is OK try erasing the code first and if the code comes back you may have to reprogram or replaced the ECM.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0657 2008 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 P0657 2008 Toyota Prius code?

Need more information on how to fix the P0657 2008 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 P0657 2008 Toyota Prius Code

1. What does the OBDII code P0657 mean on a 2008 Toyota Prius?

P0657 indicates an issue with the actuator supply voltage circuit, specifically that it is open or not functioning properly.

2. What are the common symptoms of code P0657 in a 2008 Toyota Prius?

Symptoms may include a check engine light, reduced engine performance, problems with various actuators, or the vehicle failing to start.

3. What causes the P0657 code to appear on a 2008 Toyota Prius?

The most common causes are a damaged actuator supply voltage circuit, a faulty actuator control module, corroded or loose wiring connections, or a defective PCM (powertrain control module).

4. Can I drive my 2008 Toyota Prius with a P0657 code?

It is not recommended to drive the vehicle with this code, as it can lead to further damage or unsafe driving conditions due to reduced functionality of critical systems.

5. How do I diagnose the P0657 code on my 2008 Toyota Prius?

Diagnosis involves checking wiring and connectors for damage, testing the actuator supply voltage circuit for continuity, and using a scan tool to monitor the actuator control module.

6. What is the most likely repair for a P0657 code in a 2008 Toyota Prius?

The most common repairs include fixing or replacing damaged wiring, cleaning corroded connectors, or replacing a faulty actuator control module.

7. How much does it cost to fix a P0657 code on a 2008 Toyota Prius?

Repair costs vary depending on the issue but can range from $100 for simple wiring repairs to $1,000 or more if a module replacement is necessary.

8. Can a weak battery cause the P0657 code in a 2008 Toyota Prius?

Yes, a weak or failing 12V battery can sometimes cause voltage-related codes, including P0657, by disrupting the actuator supply voltage.

9. How can I prevent the P0657 code from appearing again?

Regular maintenance, ensuring all wiring connections are secure and free from corrosion, and promptly addressing electrical issues can help prevent this code.

10. Do I need a professional mechanic to fix the P0657 code on my 2008 Toyota Prius?

While basic troubleshooting like checking for loose connections can be done at home, a professional mechanic with advanced diagnostic tools is recommended for accurate diagnosis and repair.