P0693 indicates that the Powertrain Control Module (PCM) has detected a low voltage condition in the control circuit for the secondary cooling fan (Fan 2). This usually means the fan is not receiving enough power to operate when commanded.
Corroded connectors, broken wires, or loose terminals can cause a voltage drop, leading the PCM to read a low condition.
A relay that fails to close or a blown fuse will prevent proper voltage from reaching the fan.
Internal windings or brushes can create high resistance, pulling the circuit voltage down.
A poor ground path can cause the fan circuit voltage to sag, triggering the code.
Only after ruling out wiring, relay, fuse, and fan defects should the PCM be considered, as it is an unlikely cause.
Resetting the light will not cure the underlying circuit issue; the code will return if the fault remains.
No. In real‑world experience the PCM is rarely at fault. Wiring, relay, fuse, or the fan itself are far more common causes.
If the fan does not operate, the engine can overheat, which may lead to coolant loss, head gasket stress, or reduced performance, but it does not directly damage electronic modules.
A basic scan tool to read the code and a multimeter to check voltage and resistance are sufficient for most diagnoses.