We’ve all been there before. You’re driving along and suddenly, the Check Engine Light flashes on. It might not even be accompanied by any sort of symptom – no spitting, no sputtering, no jerking. What’s going on? Of course, there are other lights that can come on in your dash, as well. They’re all indicators, but they don’t mean the same thing.
Diagnostic trouble codes
Generally, the Check Engine Light means there’s a diagnostic trouble code stored in the car’s computer. The computer has detected some sort of abnormal operation in the engine, transmission or emissions system, and it’s warning you that it needs to be checked out.
There are hundreds, perhaps thousands, of different codes that can trigger the Check Engine Light alone, and this doesn’t account for other systems with their own warning lights (TPMS, ABS, battery/alternator, oil, etc.).
While it would be impossible to list all the different codes that might light up on your dash, here is some insight into what different lights might mean.
Check Engine Light: The Check Engine Light comes on when the computer notes a problem in the emissions/exhaust system, the transmission or the engine. It could be as simple as a loose or missing gas cap, or something more serious like a failed oxygen sensor or a misfire.
TPMS: This light is part of your tire pressure monitoring system. If it comes on and stays on, then you have a tire low on air, or there’s a problem with a sensor or the system.
ABS: This light warns you about a problem with your anti-lock braking system. It does not mean that you won’t be able to stop the car, but it does mean that the ABS system may have been disabled.
Oil Pressure Light: The Oil Pressure light means that the computer has detected a drop in oil pressure. Your oil might be low, the sending unit might have failed, or the pressure sensor may be bad.
Battery: The Battery light means that there’s an issue with your battery or alternator; generally, it’s a sign that your battery’s charge is abnormally low.
Coolant Temperature Light: The Coolant Temperature light comes on to warn you that the temperature of your engine coolant is too high and you need to pull over and turn off the engine before it overheats.
Brake Light: The Brake light comes on to show the parking brake is engaged, or that the brake fluid is low.
These are just a few of the warning lights on your dash. Some of these systems will store a trouble code, and others will not. The best option is to have a mechanic inspect your car as soon as possible.
This article originally appeared on YourMechanic.com as What Are the Different Codes That Can Light Up on My Dashboard? and was authored by Valerie Johnston.