P0604 — Internal Control Module Random Access Memory (RAM) Error
Category: Powertrain Severity: High
Updated:
DTC code P0604 means: Internal Control Module Random Access Memory (RAM) Error. It falls under the "Powertrain" category, with an estimated severity of High. Common causes include eCM/PCM software not programmed correctly or corrupted, low or unstable battery voltage during a previous update and internal ECM/PCM hardware fault; it's worth confirming the diagnosis before replacing parts.
Possible causes
- ECM/PCM software not programmed correctly or corrupted
- Low or unstable battery voltage during a previous update
- Internal ECM/PCM hardware fault
Symptoms
- Check engine light on
- Erratic engine behavior or stalling
- Other modules may also show faults
- Vehicle may fail to start in severe cases
How to diagnose it step by step
- Check battery and grounds.
- Update the software.
- Repair or replace the ECU.
How to fix it
This code points to the engine computer itself. Check battery voltage and connections first (a weak battery during a software update is a common cause). If the fault persists, the ECM/PCM usually needs reprogramming or replacement at a specialized workshop or dealer.
Estimated repair cost
$100–1,500.
Frequently asked questions
What does DTC code P0604 mean?
Internal Control Module Random Access Memory (RAM) Error.
Is code P0604 serious?
Severity High. Have it checked as soon as possible, especially if it affects safety or the catalytic converter.
Can I keep driving with code P0604?
Not recommended.
Related codes
P0603 P0605 P0602 P0606 P0601 P0600 P0615 P0620 P0627 P0641
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