Is it bad to always leave the OBD2 scanner plugged into the car?

OBD2 scan tools have become very popular for reading our vehicles’ fault codes and finding out what’s wrong with them before taking them to a repair shop. Some people also use them to clear certain error codes from the dashboard. But the truth is, they have many more uses.

Some mobile apps, such as Torque, connect to your car’s OBD2 interface via Bluetooth or the Wi-Fi network generated by the OBD2 device itself. Then, we can view all the car’s telemetry in real time while it’s in use, which is fantastic if you know a little about mechanics, or if you’re simply curious about your car’s turbo pressure, the airflow meter reading, or the fuel consumption being measured by the ECU.

And, of course, if you like seeing all this info—and don’t want to clutter your dashboard with physical gauges like some people do—you’ll probably have a question. Can you leave the OBD2 scanner plugged into the car, or do you have to plug it in and unplug it every time you want to use it?

What are the risks of keeping the OBD2 plugged into the car?

We could start the discussion by talking about whether it’s dangerous to drive with an OBD2 device connected to the car. And, in general, we have to acknowledge that there aren’t sufficient reasons to advise against it. However, there are some drawbacks that can arise:

Battery Drain

When the car is running, the device is powered by the car’s own electrical system, so there’s no problem. However, as we’ll see a little later, leaving an OBD2 device plugged in can drain the car’s battery.

Distractions While Driving

Whether it’s the device’s own light or the urge to read the ECU data on your phone while driving. In general, it’s best to keep anything out of your line of sight that might distract you from driving.

Connector Damage

Keeping the device plugged in constantly could even damage the port, especially if it’s near your knees and you bump it while driving. Repairing it isn’t too complicated, but it’s a rare issue that’s easily preventable.

Discomfort While Driving

Every car has the OBD2 port in a different location. In many cars, it’s located in the driver’s area, at knee level, which can interfere with a comfortable driving position.

Can OBD2 Drain My Car’s Battery?

Yes, but it’s not common. It depends largely on the condition of the car’s battery and the type of OBD2 device being used. OBD2 devices initially use very little power to operate and shouldn’t shorten the battery’s lifespan in any way. However, a poorly designed OBD2 device—and we know that many of those sold on AliExpress are—can drain your entire battery if you leave it plugged into the port.

If you use your car daily and aren’t going to leave it parked for weeks without touching it, you can leave the OBD2 device plugged into the port. But remember that it will continue to consume a small amount of power. If you aren’t going to drive the car for a while, it’s best to unplug the device.

How often can I plug in and unplug my OBD2 devices?

Although the port can be damaged with use, there’s no evidence of cases where these ports have been damaged by plugging devices in and out. You can unplug and replug your OBD-II devices fairly often without worrying too much.

That said, if you’ve decided to use it while driving, it’s best to avoid unplugging it if you’re going to use the car several times a day.

Is the car’s OBD-II port always active?

Yes, the car’s OBD-II port is always powered. However, to perform real-time diagnostics, the vehicle must be turned on.

Can the OBD2 port be turned off?

Rather than turning it off, you can disable it, but we don’t recommend doing so. Many modern vehicles require the OBD2 port to be enabled so that ITV technicians can perform diagnostics during the inspection. Disabling this technology will only cause problems.

What you can do is buy an OBD2 scanner that has an on/off switch. This way, you’ll avoid unnecessarily draining the battery when the car is turned off.

OBD2 Scanner Left Plugged In All the Time: Yes or No?

If we had to take a stand, we’d say it’s not worth it. If you use your car every day, an OBD2 scanner shouldn’t cause you any problems. However, if you plug one in and leave the car parked for a month, you can be sure the battery will be completely drained.

As an alternative, you can use an OBD2 extension cable with a switch in your car. This accessory will let you place the connector in a more convenient spot, while also giving you access to a button to cut off the power and prevent the battery from draining. Just remember to turn it off.

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