P0604 2004 Toyota Prius 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 2004 Toyota Prius 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.
Code P0604 2004 Toyota Prius Description
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.
What are the Possible Causes of the DTC P0604 2004 Toyota Prius?
- 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 2004 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.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0604 2004 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.
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Frequently Asked Questions about P0604 2004 Toyota Prius Code
1. What does the OBDII code P0604 mean on a 2004 Toyota Prius?
P0604 indicates an Internal Control Module Random Access Memory (RAM) error, meaning the Engine Control Module (ECM) has detected an issue with its internal memory.
2. What are the common symptoms of the P0604 code in a 2004 Toyota Prius?
Symptoms may include a check engine light, poor engine performance, stalling, difficulty starting, or unusual transmission behavior.
3. What causes the P0604 code to appear on a Toyota Prius?
Common causes include a faulty ECM, electrical shorts, corroded or loose wiring, or a failing 12V battery causing voltage irregularities.
4. Can a weak 12V battery trigger the P0604 code in a 2004 Toyota Prius?
Yes, a weak or failing 12V battery can create voltage issues that may trigger the P0604 code.
5. How is the P0604 code diagnosed in a Toyota Prius?
Diagnosis typically involves checking the ECM for faults, inspecting wiring and connectors for damage, and testing the 12V battery for proper voltage.
6. Can the P0604 code cause the car to stop working completely?
Yes, in severe cases, the ECM may fail to function properly, potentially causing the vehicle to lose power or not start.
7. Is it safe to drive a Toyota Prius with the P0604 code?
Driving with this code is not recommended, as it may lead to further damage or unpredictable vehicle behavior.
8. How do you fix the P0604 code on a 2004 Toyota Prius?
Fixes may involve repairing damaged wiring, replacing the ECM, or resolving battery and voltage issues.
9. How much does it cost to repair the P0604 code on a Toyota Prius?
Repair costs vary but can range from $100 for minor electrical fixes to over $1,000 if the ECM needs replacement.
10. Can the P0604 code clear itself after repairs?
If the underlying issue is resolved, the code may clear after a few drive cycles, or it can be manually cleared using an OBDII scanner.
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