Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0604: Internal Control Module Random Access Memory (Ram) Error: Notes
DTC detecting condition:
Immediately at fault recognition
Trouble symptom:
- Engine does not start.
- Engine stalls.
- CHECK DTC.
Read the engine DTC using the Subaru Select Monitor or general scan tool. Refer to ENGINE (DIAGNOSTICS) (W/O STI)>READ DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC other than P0604 displayed? (Current malfunction)
Yes: Check the appropriate DTC using the "List of Diagnostic Trouble Code (DTC)". Refer to ENGINE (DIAGNOSTICS) (W/O STI)>LIST OF DIAGNOSTIC TROUBLE CODE (DTC) .
No: Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.
NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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