AutoCodesToyota – P0604 2007 Toyota Highlander

P0604 2007 Toyota Highlander Code - Internal Control Module Random Access Memory Error

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 (ECM) Harness power supply circuit is open or shorted, Engine Control Module (ECM) Programming. 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
P0604 2007 Toyota Highlander indicates Internal Control Module Random Access Memory Error.
Common causes
Common causes include Faulty Engine Control Module (ECM), Engine Control Module (ECM) Harness power supply circuit is open or shorted, Engine Control Module (ECM) Programming.
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.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 1,832
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jun 14, 2020
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Code P0604 2007 Toyota Highlander 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 P0604 2007 Toyota Highlander - Internal Control Module Random Access Memory Error - AutoCodes.com
P0604 2007 Toyota Highlander Code - Internal Control Module Random Access Memory Error

What are the Possible Causes of the DTC P0604 2007 Toyota Highlander?

  • Faulty Engine Control Module (ECM)
  • Engine Control Module (ECM) Harness power supply circuit is open or shorted
  • Engine Control Module (ECM) Programming

How to Fix the DTC P0604 2007 Toyota Highlander?

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.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0604 2007 Toyota Highlander 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 P0604 2007 Toyota Highlander code?

Need more information on how to fix the P0604 2007 Toyota Highlander 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 P0604 2007 Toyota Highlander Code

1. What are the common symptoms of OBDII code P0604 in a 2007 Toyota Highlander?

- Common symptoms include the Check Engine light illuminating on the dashboard, poor engine performance, and potential issues with the transmission shifting.

2. What does the OBDII code P0604 on a 2007 Toyota Highlander indicate?

- OBDII code P0604 indicates an Internal Control Module Random Access Memory (RAM) Error in the vehicle's Engine Control Module (ECM).

3. What are the possible causes of OBDII code P0604 in a 2007 Toyota Highlander?

- Possible causes of P0604 include a faulty ECM, electrical interference, software malfunction, or issues with the ECM's connection.

4. How can I diagnose OBDII code P0604 in my 2007 Toyota Highlander?

- Diagnosing P0604 typically involves using a diagnostic scanner to retrieve the code, checking for any related symptoms, and inspecting the ECM for physical damage or loose connections.

5. Can I still drive my 2007 Toyota Highlander with the P0604 code present?

- It is not recommended to drive the vehicle with the P0604 code present, as it can lead to further damage and potentially unsafe driving conditions.

6. How can I repair OBDII code P0604 in my 2007 Toyota Highlander?

- Repairing P0604 may involve reprogramming or replacing the ECM, addressing any underlying electrical issues, or seeking professional assistance for a thorough diagnosis and repair.

7. Is it possible to reset the OBDII code P0604 in a 2007 Toyota Highlander?

- Resetting the code may temporarily clear it, but if the underlying issue is not addressed, the code is likely to reappear. It's important to diagnose and repair the root cause of the problem.

8. Can a DIY enthusiast fix OBDII code P0604 in a 2007 Toyota Highlander?

- While some basic troubleshooting steps can be taken by a knowledgeable DIY enthusiast, diagnosing and repairing P0604 often requires specialized tools and expertise. Professional assistance is recommended.

9. How much does it cost to repair OBDII code P0604 in a 2007 Toyota Highlander?

- The cost of repairing P0604 can vary depending on the underlying issue, the need for ECM reprogramming or replacement, and labor costs. It's advisable to obtain quotes from reputable mechanics or dealerships.

10. Will OBDII code P0604 cause my 2007 Toyota Highlander to fail an emissions test?

- Yes, having the P0604 code stored in the ECM can cause your vehicle to fail an emissions test due to the potential impact on engine performance and emissions control systems.

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