P0481: Fan 2 Control Circuit

The engine module switches the radiator fan either through a relay, whose coil it pulls to ground, or with a PWM signal to a fan control module. The circuit is an output that CARB requires to be checked continuously. P0481 concerns the second fan control circuit – depending on the design a second fan or a second speed stage; on GM and Saab, relays 2 and 3 switch the fans in series or parallel for low and high speed. GM sets it for an open circuit (200 kΩ or more, 50 of 63 samples, MIL after two trips) and reports shorts as P0693/P0694. Ford's OBD summaries do not contain the code. One fan stage then fails or runs constantly; cooling usually remains partly available.

Symptoms

• Check engine light on
• One fan stage or fan not working, or running constantly
• Temperature rises at standstill

Most likely causes

• Fan relay 2 (or 2/3) faulty
• Corrosion or water in relay or fan connector
• Control wire open or shorted to ground
• Driver in the engine module

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 actual temperature in live data
3. Make sure the fan comes on when it should
4. Check the thermostat and connector
5. Measure the sensor and replace it if its readings do not make sense

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P0481 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 4: Emissions
• 81: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0481?

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 P0481?

The most common causes are: fan relay 2 (or 2/3) faulty; corrosion or water in relay or fan connector; control wire open or shorted to ground.

Related codes

• P0480Fan 1 Control Circuit
• P0482Fan 3 Control Circuit
• P0483Fan Rationality Check
• P0693Fan 2 Control Circuit Low
• P0694Fan 2 Control Circuit High
• P0217Engine Coolant Over Temperature Condition

Sources

• gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
• saabwisonline.com: dtc p0481 w lf1
• saabwisonline.com: dtc p0480 or p0481 ldk or lhu

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.