FAQ and Troubleshooting
This page is a reference guide — it shows where to find answers to common questions, how to troubleshoot adapter and app issues, and covers additional topics not listed in the main FAQ. The canonical list of 20 frequently asked questions with answers lives on the /en/faq/ page.
Where do I find answers to common questions?
Car Diagnostics has several support tiers depending on question complexity:
| Question type | Where to go | Example |
|---|---|---|
| General platform questions | /en/faq/ — 20 most common Q&A | ”How do I connect the adapter?” |
| How to use the app | /en/docs/usage-overview/ | “How do I read DTC codes?” |
| Adapter setup | /en/docs/adapter-pairing/ | “Adapter not found on Bluetooth” |
| Billing and plans | /en/docs/billing-overview/ | “How much does Pro cost?” |
| Roles and permissions | /en/docs/roles-overview/ | “How do I add a mechanic?” |
| Getting started | /en/docs/getting-started/ | “What do I need for the first scan?” |
| Technical support | Email: [email protected] | ”Payment error” |
What should I do if the adapter won’t connect?
OBD-II adapter connection problems are the most common support issue. Follow this step-by-step flow:
- Check power. Turn the ignition on (the engine does not need to be running). The adapter’s LED should light up.
- Check Bluetooth. Open your phone’s Bluetooth settings. The adapter should appear in the available devices list. If not, remove the old pairing and try again.
- Verify compatibility. Not all ELM327 adapters work with Car Diagnostics. Check your adapter against the supported list on the Connecting an OBD adapter page.
- Try another vehicle. If the adapter won’t connect to your car, test it on a different vehicle — this helps determine whether the issue is with the adapter or vehicle compatibility.
How do I know if my adapter is faulty?
Plug the adapter into a vehicle with the ignition on. If the power LED does not light up, the adapter is likely faulty. If the LED works but the app does not see the adapter after pairing, try resetting it with the ATZ command (if your adapter supports AT commands via a terminal app) or unplug it from the OBD-II port for 30 seconds to force a full power cycle.
How do I report a bug in the app?
If you encounter a bug or incorrect behavior, email [email protected] with the following information: app version (from Profile → About), Android model and version, vehicle model and year, and a step-by-step description of what you were doing before the issue occurred. For crashes during diagnostics, include the in-app logs (tap “Send logs” on the error screen) — this significantly speeds up the fix.
Is there a public API?
Car Diagnostics does not currently offer a public REST or WebSocket API for third-party developers. Integration with external services (repair shops, fleet management platforms, marketplaces) is on the roadmap. If you have an integration need, email [email protected] — we may be able to arrange early access.
How do I become a beta tester?
New features are first tested in a closed beta channel. To join:
- Email [email protected] with the subject “Beta test”.
- Include your account email and phone model.
- Once approved, you will receive a link to the beta version via Google Play Console (closed testing track).
The beta version may contain unstable features; use at your own risk.
Is iOS / iPadOS support planned?
Car Diagnostics is currently Android-only. This is due to a technical limitation: OBD-II communication over Bluetooth Classic (SPP) is blocked on iOS at the OS level. Apple only allows SPP through the MFi (Made for iPhone) program, which requires a dedicated chip in the adapter. We are evaluating the market and considering BLE/Wi-Fi adapter support for iOS.
Can I diagnose LPG / diesel / hybrid / electric vehicles?
Yes, Car Diagnostics supports scanning any engine type: gasoline, diesel, LPG, hybrid, and electric. For diesel vehicles, the app reads DPF (diesel particulate filter), EGR, and Common Rail injection system codes. For LPG vehicles: the app reads fault codes through the standard OBD-II port — if the LPG controller is connected to the CAN bus, its codes appear just like any other module codes. For hybrid and electric vehicles, powertrain-specific codes (battery management, electric motor, inverter) are read when supported by the vehicle’s ECU.
What are the Free tier limitations?
The Free tier includes: 1 vehicle in your profile, basic DTC scanning, live telemetry (PIDs), session history, report viewing. What is NOT included: AI code explanation, AI agent chat, predictive maintenance, PDF reports, multi-user support. If you need AI analysis, upgrade to Personal or Pro from the Subscription screen in the app.
Top 5 real support cases
Recent user-reported issues and their resolutions — to set expectations on what gets solved fast:
1. “Adapter works on my neighbor’s car but not mine.” Most common cause: older vehicle (pre-2001) may lack an OBD-II port and only have OBD-I. Check: OBD-II became mandatory in the US in 1996 and in the EU in 2001 (petrol) / 2004 (diesel). Cars older than that in EU may not communicate.
2. “Live PIDs lag, updating every 5 seconds.” Bluetooth Classic ELM327 is physically limited to ~10-25 commands/sec. If you need 5+ Hz logging, switch to a WiFi or BLE 5.0 adapter with ELM327 v2.2+ (3-4× the throughput). Details: OBD adapter WiFi vs Bluetooth vs BLE.
3. “Read P0420, replaced the catalyst, code came back.” 60% of the time P0420 is the downstream O2 sensor — not the catalyst itself. Correct diagnosis: view live O2 sensor waveforms on the paid tier — the downstream signal should be flat if the catalyst is healthy.
4. “AI agent says one thing, my mechanic says another.” AI relies on statistics of typical faults for your VIN. Mechanic sees the physical condition. Best practice: use AI recommendations as hypothesis #1, then have the mechanic confirm with “AI suggests X, verify before replacing Y.” This avoids “swap everything until it works.”
5. “Cleared DTC, Check Engine came back after a day.” Clearing wipes memory but doesn’t fix the root cause. After 1-3 drive cycles (ECU re-tests systems), the code returns if unresolved. Never clear before an emissions inspection — it also resets readiness monitors, and the test station will see “Not Ready” and refuse to certify.
More questions? — contact us and we’ll add them here.