What causes a P0645 code?

Common causes: Failed relay; Wiring.

What are the symptoms of a P0645 code?

Typical symptoms: AC inoperative; CEL.

Yes — this code is generally safe to drive with, but address it soon to avoid escalation. Estimated repair: $50-$250.

OBD-II Code · HVAC

A/C Clutch Relay Control Circuit

low severitySafe to drive$50-$250

AC clutch relay circuit fault.

Common symptoms

Likely causes

Where to start

Try the cheapest cause first. Start by checking: failed relay.
Cost & scope. $50-$250
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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