Use your PC or phone to scan your vehicle’s OBD-II system diagnostics
ELM327 Bluetooth devices provide an easy way to scan a vehicle’s Onboard Diagnostics II (OBD-II) system for codes. They can also read PIDs and help in diagnosis. These devices are an inexpensive way for DIYers and experienced technicians to tackle computer diagnostics. However, there are some problems with Bluetooth ELM327 that you should be aware of before buying one.
The most common problem with ELM327 Bluetooth devices is that some low-cost scanners include unauthorized ELM327 microcontroller clones. These clone chips often exhibit strange behavior, but even legitimate hardware doesn’t work with some devices. If you want to use an iOS device as an analysis tool, it is especially important to pay attention to these issues.
ELM327 Bluetooth Enabled Hardware
Scan tools that include an ELM327 microcontroller and Bluetooth chip can be paired with a variety of devices, but there are significant limitations. The main devices you can use an ELM327 Bluetooth scan tool with are:
- smart phones
The most convenient way to take advantage of ELM327 Bluetooth connectivity is to pair a scanner with a phone, but not all phones work well with this technology. The main exceptions include Apple iOS products like the iPhone, iPad, and iPod touch.
These iOS devices generally do not work with ELM327 scanners due to the way Apple manages the Bluetooth stack. Most generic ELM327 Bluetooth devices do not pair with Apple products, which means Apple users are better off with ELM327 USB and Wi-Fi scanners.
In some cases, other smartphones may have pairing issues with some ELM327 Bluetooth scanners. This is usually due to issues with unauthorized cloned microcontrollers that do not have updated code.
ELM327 Bluetooth Device Pairing
Aside from the situations described above, pairing ELM327 Bluetooth devices with smartphones, tablets, and PCs is usually a straightforward procedure. The most common steps are:
Plug the ELM327 Bluetooth dongle into the OBD-II port.
Set your smartphone, tablet, or laptop to scan for available connections.
Select the ELM327 scan tool.
Enter the pairing code.
In most cases, the documentation that comes with an ELM327 Bluetooth scanner includes the pairing code and special instructions that differ from this basic outline. If no documentation is included, try one of the common codes, including:
If these codes don’t work, other sequential sets of four numbers are sometimes used.
What to do when pairing fails
If your ELM327 Bluetooth scanning device is not pairing with your smartphone, there are several possible causes. The first step is to try other pairing codes. Then pair the scanner with another device. Some faulty cloned ELM327 microcontrollers have problems connecting to certain devices, and your scanner may pair with a laptop while refusing to connect to your phone.
Another thing that can cause pairing failure is the limited amount of time your scanner remains discoverable. Most ELM327 Bluetooth scanners become discoverable as soon as you plug them in, but become undiscoverable after a while. If you perform the pairing operation within one minute of plugging the scan tool into the OBD-II socket, there should be no problem.
If your scan tool still won’t pair, the device may be faulty. This is the main reason why it is a good idea to stay away from cheap and cloned scanners. Buy a scanner from a retailer that stands behind their products.
ELM327 Bluetooth Alternatives
Alternatives to ELM327 Bluetooth scanners are devices that use Wi-Fi and USB connections. ELM327 Wi-Fi scanners are generally more expensive than devices that use Bluetooth, but can be used with Apple products. Most ELM327 USB scanners are not designed for use with Apple products, but some Apple-authorized options can be used with the Dock Connector.