FAQ
TL;DR: For ELM327 + ScanTool, use 38400 bps and pick the single working COM port; “Torque on Android is 100x better.” [Elektroda, tzok, post #16716671]
Why it matters: This FAQ helps you connect ELM327 adapters to PCs or phones and pick working software for basic OBD data.
Quick Facts
- ELM327 communicates at 38400 bps; Device Manager port speed doesn’t change this. [Elektroda, tzok, post #16716671]
- Bluetooth pairing can expose two COM ports, but only one will work reliably. [Elektroda, bubu1769, post #16714455]
- Older ScanTool builds may struggle on Windows 10 due to compatibility or drivers. [Elektroda, gimak, post #16716681]
- Wi‑Fi ELM327 worked with CarScanner/Torque on phones; a BT clone showed “clone detected” and failed in cars. [Elektroda, wojak510, post #16717758]
- ScanTool was already ~10 years old in 2017; consider newer, car‑specific tools. [Elektroda, kkknc, post #16715113]
Can ScanTool 1.13 connect to an ELM327 over Bluetooth on Windows?
Yes, if you first pair the adapter in Windows and select the correct COM port in ScanTool. Only one of the two exposed COM ports typically works. However, users reported ScanTool is dated and not worth the effort compared to modern apps. [Elektroda, bubu1769, post #16714455]
How do I pair a Bluetooth ELM327 and pick the right COM port?
- Pair the ELM327 in Windows Bluetooth settings and note the created COM ports.
- Open ScanTool and choose the working COM from its port list.
- If two ports appear, test each; only one will communicate correctly. “It has two COM ports detected but it works only under one.” [Elektroda, bubu1769, post #16714455]
What baud rate should I set for ELM327 with ScanTool?
Use 38400 bps. Changing the baud rate in Device Manager does not affect ELM327 communication. ScanTool v1.21 can also talk on higher COM numbers (e.g., COM30), avoiding manual renumbering. “ELM-327 uses a speed of 38400bps.” [Elektroda, tzok, post #16716671]
Why won’t ScanTool connect on Windows 10?
An old ScanTool build may be incompatible with Windows 10 or lack proper drivers. Users noted newer Windows versions can block legacy diagnostic apps from accessing the adapter, even when pairing succeeds. Try updated software or a different OS. [Elektroda, gimak, post #16716681]
Which ScanTool version should I try first?
Try ScanTool 1.21. It removes the need to force low COM numbers and can use higher ones like COM30. Keep the adapter at its native 38400 bps and select the discovered working COM in-app. [Elektroda, tzok, post #16716671]
Is Torque for Android better than ScanTool on PC for basics?
Yes. Users report Torque is far more capable for generic OBD data. “Torque on Android is 100x better than ScanTool.” If you only need engine PIDs and codes, Torque or CarScanner on a phone often connects faster and logs more cleanly. [Elektroda, tzok, post #16716671]
What can I read with a generic ELM327—will it cover ABS or airbag?
Expect engine-only diagnostics with generic ELM apps. Features like ABS or airbag are typically not available. One user noted these tools allow engine diagnostics only and that coverage is incomplete. Use brand-dedicated software for extended modules. [Elektroda, Killlu, post #16719557]
Why does my cheap ELM327 connect to a phone but fail on PC?
Low-quality clones can show “ELM clone detected,” fail to pair stably, or refuse to connect in some cars. Phones may connect over Wi‑Fi while the same hardware’s Bluetooth path remains unreliable. Swap adapters or use Wi‑Fi with known-good apps. [Elektroda, wojak510, post #16717758]
Can I view O2 sensor voltage and LTFT/STFT with universal ELM apps?
Do not count on exact voltages or complete fuel trim data with universal software. Coverage varies by vehicle, and some apps show only peak or partial values, limiting diagnosis. “Do not count on any universal program under ELM to see the exact voltage.” [Elektroda, kkknc, post #16716723]
How can I use a Wi‑Fi ELM327 with PC programs that expect a COM port?
ScanTool expects a serial COM device. A Wi‑Fi ELM327 provides TCP/IP, not a serial port. Without extra virtual COM software or custom coding, you can’t attach it directly like Bluetooth/USB. One reply bluntly noted you’d need to write something yourself. [Elektroda, kkknc, post #16717784]
What should I do when ScanTool shows multiple COM ports for my adapter?
Pick the single working COM. Bluetooth stacks often create two ports (inbound/outbound), but only one carries ELM data. Test each within ScanTool until connection succeeds, then save that port for future sessions. [Elektroda, bubu1769, post #16714455]
Is ScanTool still worth using today?
It’s considered outdated. Users in 2017 already called it ~10 years old and suggested choosing software dedicated to your car brand or modern cross-platform apps instead. Expect limited functions versus newer tools. [Elektroda, kkknc, post #16715113]
Which alternative PC programs were suggested for ELM327?
PCMSCAN and ScanMaster were named as more usable PC options. A user reported wasting time with ScanTool and preferred these programs for general engine diagnostics. Evaluate features against your vehicle’s needs. [Elektroda, Killlu, post #16719557]
Why is my data refresh so slow with a Bluetooth ELM327?
Cheap ELM327 adapters often refresh slowly. Bluetooth pairing may succeed, yet PID updates lag, making live data less useful. Upgrading the adapter or switching to a reliable app can improve responsiveness. [Elektroda, bubu1769, post #16714455]
