Fan 2 relay stuck closed or failing internally; Damaged wiring in the fan 2 control circuit, such as a short to voltage or chafing against another live wire; Corroded or loose connector at the relay, fan or control module; Faulty fan control module or integrated fan driver (on vehicles that have one); Water or corrosion in the relay or fuse box; Fault inside the powertrain control module output driver.

P0694

Fan 2 Control Circuit High.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
6: AreaComputer and output circuits
94: FaultThe specific fault in that area

What it means

P0694 means the powertrain control module has detected a high voltage or a stuck-on condition in the control circuit for cooling fan 2 (generic SAE J2012 definition). The module monitors the circuit that drives the fan relay or fan driver and sees a voltage or state that does not match the command it is sending. How fan 2 is arranged (a separate fan, a second speed, or a relay-driven stage) depends on the vehicle.

Symptoms

Cooling fan 2 running constantly, even with the engine cold or the ignition off
Cooling fan 2 not running at all when the engine is hot
Engine temperature rising in traffic or at idle
Air conditioning performing poorly at standstill
Engine warning light on
Battery going flat after the car has been left standing

Possible causes

Fan 2 relay stuck closed or failing internallylikely
Damaged wiring in the fan 2 control circuit, such as a short to voltage or chafing against another live wirelikely
Corroded or loose connector at the relay, fan or control modulepossible
Faulty fan control module or integrated fan driver (on vehicles that have one)possible
Water or corrosion in the relay or fuse boxpossible
Fault inside the powertrain control module output driverrare

How to diagnose

Read all stored codes and freeze frame data, and note whether other cooling, temperature or air conditioning codes are present.
Check coolant level and condition, then inspect the fan, relay box and wiring for visible damage, water ingress, melted plastic or rubbing.
Check whether fan 2 runs with the ignition off or the engine cold, and whether it can be switched on and off using the scan tool's bidirectional fan control, if the vehicle supports it.
Swap the fan 2 relay with an identical known-good relay (where the wiring diagram confirms it is the same type) and retest.
Inspect the relay socket, fan connector and module connector for corrosion, bent pins or heat damage.
With the relay removed, check the control wire for unexpected voltage and for continuity and shorts to power or earth against the wiring diagram.
Check the fan supply and earth feeds and the fuse, using voltage drop testing under load.
If the wiring and relay are good, test the fan control module or powertrain control module output according to the manufacturer's procedure.

How to fix

Replace the faulty fan 2 relay with the correct specification part.
Repair or replace the damaged section of wiring that is shorted to voltage.
Clean or replace corroded connectors and terminals, and dry out and repair any water ingress in the relay box.
Replace the faulty fan control module or fan assembly if testing shows the driver has failed.
Repair or replace the powertrain control module only after all wiring and component faults are ruled out, following the manufacturer's procedure.

Can I keep driving?

Medium severity

Short, careful journeys are usually possible if the fan is working, but a fan that is stuck on can flatten the battery and a fan that will not run risks overheating. Watch the temperature gauge, and stop at once if it climbs; get it repaired soon.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.