What causes a P0634 code?

Common causes: PCM heat sink issue; Engine bay overheating; Failing PCM.

What are the symptoms of a P0634 code?

Typical symptoms: CEL; Possible PCM shutdown.

Yes — this code is generally safe to drive with, but address it soon to avoid escalation. Estimated repair: $100-$1,500.

OBD-II Code · Powertrain

PCM Internal Temperature Too High

medium severitySafe to drive$100-$1,500

PCM detected its own internal temperature is excessive.

Common symptoms

Likely causes

Where to start

Try the cheapest cause first. Start by checking: pcm heat sink issue.
Cost & scope. $100-$1,500
If the code returns after the fix: escalate to a shop or scanner with live-data and freeze-frame. A code that re-sets means the underlying fault is still there.

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