Oil Light and Engine Light On: What It Means and What to Do
The short answer
When the oil warning light and the check engine light come on together while the engine is running, treat it as a possible lubrication problem until you prove otherwise. The most common explanations are low oil level, low oil pressure, or a fault in the oil pressure sensor or its wiring. Low oil can also upset engine systems that depend on oil pressure, and the engine computer can then set its own fault code. If the oil light is red, or the dashboard shows an oil pressure warning, stop somewhere safe and switch the engine off. Running an engine without adequate oil pressure can cause serious internal damage quickly.
Exactly what each light means depends on the make, model and model year. Your owner's manual is the authoritative source for your vehicle. The guidance below describes how these warnings typically work. It is not a specification for any particular car.
First, identify which oil warning you have
Manufacturers use oil-related warnings in different ways, and the difference changes how urgent the situation is.
Warning | Typical appearance | What it usually indicates | Typical urgency; Oil pressure warning | Red oil-can symbol, sometimes with a text message | The engine is not getting enough oil pressure, or the sensor reports that it is not | Stop safely and shut the engine off; Oil level warning | Often amber or yellow, sometimes an oil can with a wavy line or a text message | Oil level is below the expected range, on vehicles equipped with a level sensor | Check the level and top up before continuing; Oil change or service reminder | Often a text message or wrench symbol | A scheduled maintenance interval has been reached | Not an immediate fault; Check engine light (malfunction indicator lamp) | Amber engine outline, steady or flashing | The engine or emissions control system has detected a fault and stored a code | Steady: diagnose soon. Flashing: reduce load and get it checked promptly
Not every vehicle has a separate oil level sensor. Symbol colors and messages also vary by manufacturer and market. Confirm which warning you are seeing in the owner's manual.
When both lights are normal
On many vehicles, both lights illuminate briefly when you switch the ignition on before starting. This is a bulb and system check. They should go out once the engine starts and settles. A momentary flicker of the oil light right at startup can also occur on some engines. If either light stays on after startup, or comes on while you are driving, that is not normal.
Common causes when both lights stay on
Low oil level: a leak or oil consumption has dropped the level far enough to trigger the oil warning, and the engine computer may also log a related fault. Low oil pressure: possible causes include a worn or failing oil pump, a blocked pickup, a clogged filter, the wrong oil viscosity, or internal engine wear. Faulty oil pressure sensor or switch, or damaged wiring: the light may be reporting a problem that does not exist. On many vehicles this also sets a check engine code for the sensor circuit. Oil-pressure-dependent systems: many modern engines use oil pressure to operate variable valve timing. Low or dirty oil can cause timing-related fault codes that turn on the check engine light. Two unrelated faults: occasionally the lights have separate causes and simply appeared around the same time.
What to do right now
If the oil pressure warning is on, pull over safely and turn the engine off. Do not keep driving to see if it clears. Wait several minutes so oil can drain back into the pan. Then check the dipstick or the vehicle's electronic oil level display with the car on level ground. If the level is low, add the oil grade specified in the owner's manual and recheck the level. Restart the engine. If the oil pressure light goes out promptly and stays out, drive cautiously and arrange an inspection to find out why the oil was low. If the oil pressure light stays on after topping up, or the oil level was already correct, do not drive the vehicle. Have it towed or inspected where it is. If you hear knocking, ticking or grinding, see smoke, or the check engine light is flashing, avoid running the engine until it has been inspected.
Reading the check engine code
The check engine light stores a diagnostic trouble code that can be read with an OBD-II scanner. Many parts retailers and repair shops will read codes for you. OBD-II is standard on most passenger vehicles sold in the United States from the 1996 model year onward. Requirements and connectors differ in other markets.
Generic codes P0520 through P0524 cover the engine oil pressure sensor or switch circuit. P0524 specifically indicates engine oil pressure too low. Codes in the P0010 to P0017 range relate to camshaft position and timing, which low or degraded oil can affect on engines with variable valve timing. Manufacturers also use their own codes, so look up any code against your specific vehicle. A code points to where the fault was detected. It does not confirm which part has failed.
Sensor fault or real pressure loss?
A sensor or wiring fault is a common and relatively inexpensive cause. However, you cannot safely assume it from the dashboard alone. The reliable way to tell the difference is for a technician to measure actual oil pressure with a mechanical gauge and compare it with the manufacturer's specification. Until that check is done, treat a persistent oil pressure warning as a genuine pressure problem.
Limits of this guide
This guide does not provide oil pressure specifications, oil capacities, light behavior for specific makes, or repair costs. These figures vary by engine and model year, and no vehicle-specific data was available for this article. For those details, use your owner's manual, the manufacturer's service information, or a qualified technician who can inspect the vehicle.
