P0604 Internal engine control module random access memory (RAM) error

P0604 – OBD-II Trouble Code Technical Description

Trouble code P0604 indicates a problem with the random access memory (RAM) of the engine control module (ECM) and/or another vehicle control module.

What does the fault code mean P0604?

Trouble code P0604 indicates a problem with the random access memory (RAM) of the engine control module (ECM) or another vehicle control module. This means that the ECM has detected a fault in its internal RAM during self-diagnosis. The vehicle's ECM continuously monitors its internal memory as well as its communication lines and output signals. The P0604 code indicates that an internal fault was detected during the ECM self-test, namely a problem with the RAM memory.

Possible reasons

Some possible reasons for the P0604 trouble code:

• Damaged or defective random access memory (RAM): One of the most common and obvious causes of the P0604 code could be a damaged or defective RAM memory in the engine control module (ECM) or other vehicle control module.
• Electrical problems: Incorrect electrical connections, short circuits or broken wires can also cause P0604, resulting in problems accessing RAM memory.
• Problems with the CAN (Controller Area Network) network: Trouble code P0604 can be caused by problems with the CAN network, which is the data bus for communication between the vehicle's various control modules.
• Problems with the control module itself: It is possible that the control module (ECM) or other vehicle control modules have internal defects or failures that cause P0604.
• Software problems: Incompatibilities or errors in the software installed on the control module can also result in a P0604 code.
• Damage or virus infection of the software: In rare cases, the vehicle control module may become damaged or infected with a virus, resulting in errors including P0604.

These reasons may be the source of the P0604 code, however, it is recommended that you contact a qualified mechanic or service center to accurately diagnose and correct the problem.

What are the symptoms of a fault code? P0604?

Symptoms for a P0604 trouble code can be varied and may vary depending on the specific system and vehicle, some of the possible symptoms are:

• Engine starting: Trouble starting or rough running of the engine may be one of the first signs associated with the P0604 code.
• Loss of power: The vehicle may experience a loss of power or a sudden drop in performance, especially when accelerating.
• Unstable idle: The vehicle may idle rough or even stall after starting.
• Unstable work: Unusual vibrations, shaking or rough running of the engine may be noticed while driving.
• Check Engine light on: When P0604 is detected, the engine management system will activate the Check Engine Light (or MIL - Malfunction Indicator Lamp) to indicate a problem.
• Transmission problems: If the P0604 code is related to the transmission control module, the vehicle may experience problems shifting gears or unusual changes in transmission performance.
• Problems with braking or steering: In some cases, the P0604 code can result in unstable brakes or steering, although this is a less common symptom.

These symptoms may manifest differently depending on the specific cause and vehicle configuration. If you experience these symptoms or your check engine light comes on, it is recommended that you take it to a qualified mechanic to diagnose and repair the problem.

How to diagnose a fault code P0604?

To diagnose DTC P0604, follow these steps:

• Reading the error code: Use a diagnostic tool to read the P0604 code from the vehicle's ECM.
• Checking Additional Error Codes: Check for additional error codes that may further indicate problems with the system.
• Checking electrical connections: Check all electrical connections, wires and connectors associated with the ECM for damage, corrosion or breaks.
• Checking battery voltage: Make sure the battery voltage is within the normal range, as low voltage may cause the ECM to malfunction.
• Checking the control module: Test the control module (ECM) to determine its functionality. This may include checking built-in test procedures or using specialized diagnostic equipment.
• Check the CAN network: Check the operation of the CAN network, including testing for short circuits or open lines.
• Checking RAM memory: Perform additional tests to evaluate the condition of the ECM random access memory (RAM).
• Updating the softwareNote: In some cases, updating the ECM software may help resolve the problem.
• Checking other control modules: Check other vehicle control modules for problems that may affect ECM operation.
• Additional tests and tests: Carry out additional tests and tests in accordance with the vehicle manufacturer's recommendations and service manual.

After diagnosing and identifying the cause of the P0604 error, you can begin to fix the problem or replace the faulty components.

Diagnostic errors

When diagnosing DTC P0604, the following errors may occur:

• Insufficient diagnostics of other components: If you do not fully diagnose all related components and systems, you may miss other causes that affect the P0604 code.
• Misinterpretation of scanner data: Incorrect interpretation of the data received from the diagnostic scanner may lead to an incorrect interpretation of the problem and, consequently, to incorrect corrective action.
• Inconsistency of information from other systems: Sometimes information from other systems or components can be misinterpreted, leading to diagnostic errors.
• Hardware or software problems: Faults in the hardware or software used for diagnosis may result in errors or incorrect conclusions.
• Incorrect interpretation of additional error codes: Incorrect detection or misinterpretation of additional error codes associated with P0604 can complicate the diagnostic process.
• Lack of updated information or technical data: If a mechanic does not have access to updated information or technical data for a specific vehicle model, it can make it difficult to diagnose and fix the problem.

To avoid mistakes when diagnosing the P0604 trouble code, it is important to follow the diagnostic process, refer to verified information, and consult with an experienced technician if necessary.

How serious is the fault code? P0604?

Trouble code P0604 should be considered serious because it indicates problems with the random access memory (RAM) of the engine control module (ECM) or other vehicle control modules. This means the vehicle may experience poor engine performance, loss of power, unstable handling, or other negative effects.

While some vehicles may continue to operate with limited functionality, in some cases the P0604 code may result in complete vehicle inoperability or even dangerous driving conditions.

In addition, ignoring this error may lead to additional damage or malfunctions in other vehicle systems. Therefore, it is recommended that you immediately contact a qualified mechanic to diagnose and repair the problem to prevent possible serious consequences.

What repair will help eliminate the code? P0604?

Troubleshooting the P0604 trouble code may involve several possible repair actions, depending on the specific cause of the problem, some of which are:

1. Replacing or flashing the control module (ECM): If the problem is due to a faulty random access memory (RAM) in the ECM, the control module may need to be replaced or flashed.
2. Checking and replacing electrical components: Check all electrical connections, wires and connectors related to the ECM. If necessary, replace damaged ones or ensure proper connection.
3. CAN network diagnostics: Check the CAN network for shorts, opens, or other problems that may interfere with communication between the ECM and other control modules.
4. ECM Software Check: Update the ECM software to the latest version, if applicable. Sometimes a software update can fix errors in the module's operation.
5. Checking for Power Issues: Make sure power to the ECM and other related components is normal. Check the condition of the battery and the operation of the generator.
6. Checking and replacing other control modules: If the problem is related to other control modules of the vehicle, it is necessary to diagnose and, if necessary, replace the defective devices.
7. Additional diagnostic tests: Perform additional tests and tests to identify any other problems that may be associated with the P0604 code.

It is important to note that repairing a P0604 code may require specialized skills and equipment, so it is recommended that you contact a qualified mechanic or service center to diagnose and repair the problem.

Check Engine Light P0604 Code Fix

P0604 – Brand-specific information

Deciphering the P0604 fault code for some well-known car brands:

1. Toyota:
   • P0604 – Internal control module RAM error.
2. Honda:
   • P0604 – Random access memory (RAM) error in the internal control module.
3. Ford:
   • P0604 – Random access memory (RAM) error in the internal control module.
4. Chevrolet:
   • P0604 – Internal control module RAM error.
5. BMW:
   • P0604 – Random access memory (RAM) error in the internal control module.
6. Mercedes-Benz:
   • P0604 – Random access memory (RAM) error in the internal control module.
7. Volkswagen:
   • P0604 – Internal control module RAM error.
8. Audi:
   • P0604 – Random access memory (RAM) error in the internal control module.
9. Nissan:
   • P0604 – Internal control module RAM error.
10. Hyundai:
    • P0604 – Random access memory (RAM) error in the internal control module.

These transcripts indicate the root cause of the P0604 code for each vehicle make. However, repairs and diagnostics may vary depending on the specific model and year of the vehicle, so it is recommended that you consult a service manual or a qualified mechanic for more accurate diagnosis and repair of the problem.