Volvo S40 Warning Lights: What They Mean

Red: stop or act now

Brake failure warning light

Possible brake system problem, such as low brake fluid. If it appears with the ABS light, the brake system may be faulty.
What to do: Stop safely, check brake fluid in the reservoir. If below MIN or BRAKE FAILURE message shows, do not drive; have the car towed. PDF page 62

Warning symbol

A fault that could affect drivability. Lights above 5 mph with an explanatory message in the information display.
What to do: Stop as soon as possible, read the display message, follow instructions or contact a Volvo technician, then press READ to erase. PDF page 58

Oil pressure warning light

Engine oil pressure is low. Brief flicker at idle after hard driving is normal if it goes off when revs rise.
What to do: Stop the engine immediately and check oil level. If normal and light stays on after restart, tow to a Volvo technician. PDF page 61

SRS system warning light

The SRS diagnostics found a fault in a belt lock or pretensioner, or airbag. Stays on over 10 seconds after start or comes on while driving.
What to do: Have the system inspected by a trained Volvo service technician as soon as possible. PDF page 61

Generator warning light

The charging system may have a fault when the light comes on with the engine running.
What to do: Have the charging system checked by an authorized Volvo workshop. PDF page 61

Parking brake applied

The parking brake is applied. PDF page 61

Seat belt reminder

A front seat occupant has not buckled their seat belt. Goes out after about 6 seconds if the car is not moving. PDF page 61

Amber: check soon

Malfunction indicator light

The OBDII computer detected a condition in engine, transmission, electrical or emission systems that may need correcting.
What to do: Have the car checked by a trained Volvo service technician as soon as possible. PDF page 60

Anti-lock Brake system (ABS)

Malfunction in the ABS; standard braking still works.
What to do: Drive to a trained Volvo service technician for inspection. PDF page 60

Tire Pressure Monitoring System

One or more tires significantly under-inflated. Flashing about a minute then staying on indicates a TPMS malfunction.
What to do: Stop and check tires soon, inflating to proper pressure. After a malfunction, have the system checked; recheck after changing tires or wheels. PDF page 200

Information symbol

Alerts you to a message in the information display; lights below 5 mph.
What to do: Press READ to erase the message, or it disappears automatically. PDF page 58

Other warnings and indicators

Occupant Weight Sensor (OWS) indicator light

Passenger's front airbag is disabled. If it stays on with the SRS light and a service message, the system has a fault. PDF page 28

Fuel level warning light

Fuel is low.
What to do: Refuel as soon as possible. PDF page 60

Alarm indicator light

Flashing every two seconds means armed; rapid flashing before ignition on means the alarm was triggered.
What to do: If a fault message appears, contact your Volvo retailer for inspection. PDF page 134

Stability system STC or DSTC

Flashes when the stability and traction control is actively working to stabilize the car. PDF page 60

Rear fog light

The rear fog light is on. PDF page 60

Green: system on

Turn signal indicator for trailer

Flashes with trailer turn signals. If it does not flash when signaling, a trailer or car turn signal is faulty. PDF page 61

Summarized in our own words from the 2011 Volvo S40 owner's manual (AI-assisted; every light name was matched against its cited page 2026-10-18). Your vehicle may not have every light, and other years can differ. A red warning that stays on usually means stop safely and check: your manual has the final word.