P0604: Internal Control Module Random Access Memory (RAM) Error
Can you still drive? Not recommended. A RAM failure can cause unpredictable engine behavior. Have the vehicle towed to a repair facility if possible.
What Does P0604 Mean?
Code P0604 indicates that the PCM has detected a failure in its internal RAM during a self-diagnostic test. RAM is used for real-time data processing including sensor inputs, calculations, and output commands. A RAM failure means the PCM cannot reliably process engine management data.
Need to read your codes?
An OBD-II scanner lets you read and clear diagnostic trouble codes from your vehicle's computer. Most scanners work with any car made after 1996.
Browse OBD-II Scanners on AmazonCommon Causes
- Internal PCM hardware failure
- Voltage spike or electrical surge damaging PCM circuitry
- Water or moisture intrusion into PCM housing
- Extreme temperature damage to PCM
- Manufacturing defect in PCM
Symptoms
- Check engine light on
- Engine in limp mode
- Poor engine performance
- Multiple random fault codes
- Possible no-start condition
Diagnostic Steps
- 1Clear the code and check if it returns immediately on key cycle
- 2Check for voltage spikes or charging system issues
- 3Inspect PCM and its connectors for water damage or corrosion
- 4Verify PCM power and ground circuits
- 5Attempt a PCM reflash
- 6If code persists, the PCM will need to be replaced
Recommended Parts & Tools
Estimated Repair Cost
| Type | Estimated Cost |
|---|---|
| Total Repair Cost Range | $300 - $1500 |
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Chat with AI About P0604Commonly Affected Vehicles
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Frequently Asked Questions
Can P0604 be fixed without replacing the PCM?
Sometimes clearing the code and reflashing the PCM can resolve a soft error. However, if the code returns, the PCM has a hardware failure and must be replaced.
What causes PCM failure?
Common causes include voltage spikes from jump starting, water intrusion, extreme heat, and age-related component degradation.
Community Fix Reports
Community reports are user-submitted and not verified by Auto AI Buddy. Results may vary.
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