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:
Detected when two consecutive driving cycles with fault occur.
Trouble symptom:
TCM RAM malfunction
- CHECK DTC.
- Perform the Clear Memory Mode using the Subaru Select Monitor. Refer to CONTINUOUSLY VARIABLE TRANSMISSION (DIAGNOSTICS)>CLEAR MEMORY MODE .
- Read the DTC.
Is DTC P0604 displayed?
Yes: Replace the TCM. Refer to CONTINUOUSLY VARIABLE TRANSMISSION(TR690)>TRANSMISSION CONTROL MODULE (TCM) .
No: Current condition is normal. Check for interference from noise, etc.
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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.