Is It Possible To Clear OBD2 Error Codes Without A Scanner?

No one likes driving their car around when the check engine light on. For one thing, it’s distractingly eye-catching, especially when you’re driving at night. Another thing that frustrates the average car owner about when the check engine light comes on is that when it does, it could mean a seemingly endless variety of problems.

If you don’t have an OBD2 scanner (get one here), it can be challenging to determine what the exact issue with your car is from the check engine light alone. Let’s break down some of the most common reasons behind the dreaded light, and then we’ll discuss how to clear it even if you don’t have a scanner so you can drive in peace once more.

Why is My Check Engine Light On?

The first thing you should do when your check engine light comes on is notice whether it’s blinking or steadily glowing. If it’s holding steady, this is an indication of a non-emergency issue with your engine functioning. However, if it’s flashing, your car is trying to tell you there’s something seriously wrong, and you should pull over right away and call for roadside assistance.

Once you’ve assessed the gravity of your situation and you determine that the light is constantly glowing, you can move on to the next step you should take when you see your check engine light come on. This step might come as a surprise to you, as it’s not exactly intuitive, and you might end up feeling just a little bit silly. Check and make sure your gas cap is securely fastened. If it’s loose, tighten it until you hear the clicking noise.

That action alone could be enough. It might seem strange, but the reasoning behind the gas-cap solution is reasonably straightforward. If that is indeed the issue behind the check engine light, your car is alerting you that fuel vapors are escaping from the gas chamber. This is a waste of gas, which of course, nobody likes to see.

However, if once you’ve tightened the loose gas cap until it clicks and the light still stays on, that doesn’t mean that the gas cap isn’t the culprit. Examine the cap for any cracks or other deformities and ensure the cap itself is not faulty.

Of course, if you’ve ruled out the gas cap, there are plenty of other problems of which your check engine light could be trying to warn you. Many of which are easily detectable, and can be dealt with without a mechanic with the help of an auto parts shop and a YouTube video. For example, maybe you need new spark plugs.

Spark plugs seal the combustion chamber of your car, leaving a gap that the spark can hop across and initiate combustion in the engine. When the spark plugs are misfiring, you’ll be aware because you’ll be able to feel a lurch when you accelerate. If you see the check engine light come on and you notice extra jerkiness when accelerating, it’s time to replace those spark plugs.

Another possible reason for your check engine light is that your oxygen sensors need to be replaced. Your oxygen sensors are essential: they monitor the amount of unburned oxygen from the exhaust and let you know how much fuel you’re burning. The more you drive, the dirtier your sensor gets, reducing gas mileage and increasing emissions. Not that I need to spell it out for you, but this is bad for your wallet and bad for the environment.

Left unchecked, this could end up being a pretty pricey problem for you. Replacing an oxygen sensor would be relatively cheap at a mechanic, and you can also do it yourself easily if you know where it is. You need to unclip the old, dirty sensor and replace it with a bright, shiny, new one.

Of course, these are only a few of the possible reasons that your check engine light could be on. Without a scanner, the only way to be sure of what’s behind your check engine light is to take it in to a mechanic and let them run their tests on it.

Clearing the OBD2 Codes

If you think you’ve solved your car’s problem, and you do decide you’d like to move forward and clear the OBD2 codes on your vehicle without a scanner, it can be done with relative ease. The only tool you’d need to have on hand is a wrench. Follow the steps below to rid yourself of the pesky check engine light:

1. Make sure your car is parked in a safe and level area. For an extra degree of safety, employ the parking brake.
2. Pop open your hood, taking care to fasten the latch, which will keep it propped open.
3. It’s time to disconnect the battery. Take the black negative (-) cable off of the battery. This is where you will need your wrench to loosen the clamps on the batteries.
4. Take the red positive (+) cable off of the battery. It’s of the utmost importance to your safety that at no point do you let the cables touch each other.
5. Once the cables are off and put off to the side at a safe distance from one another, you will need to cycle your ignition on and off anywhere from two to five times.
6. At this point, drain any power still remaining in the ECU. And this is where you can either have a lot of fun or turn an intense shade of red, depending on your personality. To drain the power, lay on the horn until it stops working. This process will usually take between 30 seconds and a minute.
7. It’s not strictly necessary, but the best practice is to wait at least 15 minutes before reconnecting the battery.
8. Place the red positive cable back on the battery, followed by the black negative cable, ensuring that both cables are securely fastened.
9. Turn the engine back on.
10. Voila! All maintenance lights should be off, considering the issue has been resolved.

If you’ve taken all the steps above and the light remains on, or if it starts to blink, make sure you take your car into your dealership or mechanic as soon as possible. Practicing safe and responsible driving is the most important way to maintain your vehicle.

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