P0694: Fan 2 Control Circuit High

The engine module switches the radiator fan relays (or the input of a PWM fan module) through output drivers and checks each control circuit electrically. GM sets a short to ground or voltage at 0.5 Ω or less after 50 of 63 samples, with the lamp after two trips; GM Europe's 2011 Saab 9-5 covers P0691–P0696 with relay assignments, the Saab 9-4X's PWM fan module reacts within 1 s. P0694 means the fan 2 control circuit is shorted to voltage; Ford's 2023 diesel checks its auxiliary fan relay within 0.5 s.

Symptoms

• Check engine light (GM after two trips)
• Fan does not run
• Rising coolant temperature in traffic or with A/C on
• A/C may be switched off to protect the engine

Most likely causes

• Control wire shorted to battery or ignition voltage
• Relay coil open or wrong relay fitted
• PWM fan module feeding voltage back onto the control line
• Engine module driver faulty

What to check, in order

Start with the simplest. You can tick off each step.

1. With the engine cold, check the coolant level; never do this when the system is hot
2. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
3. Check the actual temperature in live data
4. Make sure the fan comes on when it should
5. Check the thermostat and connector
6. Measure the sensor and replace it if its readings do not make sense

Good to know

• Repair difficulty: easy
• It affects emissions.

What each character of P0694 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 6: Control modules and outputs
• 94: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0694?

Watch the temperature gauge. If it climbs or a warning appears, stop the car in a safe place and turn off the engine: overheating can cause serious damage.

What causes code P0694?

The most common causes are: control wire shorted to battery or ignition voltage; relay coil open or wrong relay fitted; pWM fan module feeding voltage back onto the control line.

Related codes

• P0481Fan 2 Control Circuit
• P0693Fan 2 Control Circuit Low
• P0692Fan 1 Control Circuit High
• P0696Fan 3 Control Circuit High
• P0483Fan Rationality Check

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
• fordservicecontent.com: obd summary diesel 2023
• saabwisonline.com: dtc p0480 p0482 or p0691 p0696

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.