Read fault codes
Stored, pending and permanent faults, with their description and the control unit reporting them. A partial read is flagged as such.
modes 03 · 07 · 0A
CENNTIR probe · OBD2 module · pilot release
The vehicle.Its data. Your tools.
CENNTIR CAR turns a phone and a small Bluetooth OBD2 adapter into a diagnostic probe. Read fault codes with their sources, watch the engine live, keep a record of every visit — and let your AI assistant ask the car the right questions.
Android and iPhone · no AI key to enter in the app · readings work without any cloud connection.
329named OBD readings
18 805offline code definitions
15MCP tools for your AI
2platforms: Android and iPhone
01 · What you can do
Everything the OBD2 port can tell you, finally readable.
Under the steering wheel of almost every recent car sits a diagnostic port. CENNTIR CAR queries it, translates the answers and remembers them, vehicle by vehicle.
Understand, with sources
An offline base of 18,805 definitions and 32 manufacturer sections. Each explanation shows its source and licence — never a made-up answer.
offlineWatch the engine live
RPM, speed, temperatures, load, fuel trims, voltage… with the unit, quality and time of every measurement.
mode 01 · 329 readingsFreeze the moment of failure
The freeze frame restores the engine state at the exact moment the fault appeared: temperature, RPM, load, speed.
mode 02 · freeze frameGet ready for inspection
Check-engine light and emissions monitors, detailed on-board test results: know whether the car is “ready”.
monitors · mode 06Identify the vehicle
Serial number (VIN) and control-unit software IDs (CALID, CVN) so two cars or two versions are never mixed up.
mode 09One control unit at a time
Answers stay separated by control unit. You know who is speaking: the engine, the gearbox or another module on the port.
ECU 7E8 – 7EFOne file per vehicle
Each session keeps observations, notes and raw replies. Resume it later, compare before and after, export the log.
sessions · exportDrive it from your AI
Your assistant (Claude, ChatGPT or any MCP-compatible client) queries the car remotely, read-only, through the CENNTIR hub.
MCP · 15 tools
02 · How it works
From the OBD2 port to your assistant, in a single thread.
The question leaves your AI, goes through the CENNTIR hub which checks permissions, reaches the phone, then the adapter plugged into the car. The answer travels back, time-stamped and sourced.
The carOBD2 port under the wheel, ignition on
The adapterBluetooth ELM327 adapter, approved once
The phoneCENNTIR CAR, the probe: reads, decodes, records
The CENNTIR hubProbe identity, access rights, encrypted linkoptional locally
Your AIClaude, ChatGPT… over the MCP protocol
Question from the AIobd2 · read_dtcs · ECU 7E8
Answer from the car43 01 03 01 → P0301
STEP 1
Plug in the adapter
Under the steering wheel, into the OBD2 port. Turn the ignition on or start the engine.
STEP 2
Open CENNTIR CAR
Start the probe, scan for the adapter, approve it once. Readings work right away, no account, no cloud.
STEP 3
Read, or have it read
Check codes and data on the spot, or enable the hub with a QR code so your AI assistant can run the diagnosis with you.
03 · Your AI in the driver’s seat
You describe. It asks the car.
CENNTIR CAR ships no AI and asks for no key: your assistant comes to the probe, over the MCP protocol. It picks the useful readings, matches codes with sources and logs everything in the vehicle’s session.
- 15 tools exposed: status, adapters, named readings, fault codes, references, sessions and notes.
- Read-only remotely: no clearing, no coding, no actuators, no raw frames.
- Permissions checked twice: by the CENNTIR hub, then by the probe itself.
- Facts, not guesses: “NO DATA” is never presented as a healthy car.
AI assistant · CENNTIR CAR probesample exchange
The check-engine light came on in the Audi this morning. Can you see what the car says?
→ obd2 · connect · OBD BLE
→ obd2 · read_dtcs · stored, pending, permanent
→ obd2 · read_dtcs · stored, pending, permanent
The engine control unit (7E8) has stored P0301: misfire detected on cylinder 1. Nothing pending or permanent. Shall I look at the moment it appeared?
Yes, go ahead.
→ obd2 · query · freeze_dtc, freeze_engine_rpm, freeze_coolant_temperature
Freeze frame: warm engine (88 °C), idling at 812 rpm. First thing to check: cylinder 1 spark plug and coil. I’ve logged everything in the Audi’s session — and I won’t clear anything without you.
04 · The engine, live
Measurements that keep their context.
Every value comes with its unit, raw reply and time. Local tracking records one minute of data to catch a hesitation or a temperature rise.
0
rpm
Engine speed
PID 01 0C
0
km/h
Speed
PID 01 0D
0
°C
Coolant
PID 01 05
0
%
Engine load
PID 01 04
Engine speed · 60-second trackingsample values
05 · The app
Built for the car park, not the lab.
Dark background, boosted contrast, big lime buttons: readable in full sun as well as in a garage. Screenshots of pilot release 0.6 (French interface).
06 · Safety and trust
Read first. Act only when you decide.
A car is no place for experiments: CENNTIR CAR applies strict safeguards, from the adapter all the way to the AI.
- Read by default: no command changes the vehicle without an explicit action on the phone.
- Adapter approved locally: the probe only talks to adapters you have approved.
- Your data stays on the phone: the hub is only used if you enable it, for remote control.
- Traceability: raw replies, units, quality and dates kept and exportable.
- Honesty: a code that does not come back is not a confirmed repair.
Clearing a fault: four locks
- On the phone onlyNo remote tool can clear codes. Your AI may suggest it, not do it.
- First confirmationThe codes involved and the consequences are shown again.
- Second confirmationTo prevent a reflex tap.
- Single-use native tokenThe command can neither be replayed nor triggered by mistake.
07 · Hardware
What you need.
A phone, an adapter costing a few tens of euros, and a car with an OBD2 port — standard on recent vehicles.
A phone
Android or iPhone. On iPhone, the app stays in the foreground while reading.
Android 10+ · ARM64
iPhone · Bluetooth LE
iPhone · Bluetooth LE
An OBD2 adapter
Bluetooth ELM327 adapter. Profile detected automatically.
BLE FFF0 / FFE0 · OBDLink CX
Bluetooth Classic (Android)
Bluetooth Classic (Android)
An OBD2 car
Generic engine and emissions diagnostics. Available data depends on the vehicle.
CAN 11-bit · ECU 7E8–7EF
petrol ≥ 2001 · diesel ≥ 2004 (EU)
petrol ≥ 2001 · diesel ≥ 2004 (EU)
The CENNTIR probe prototype
Our own ESP32-based adapter: direct CAN reading and Bluetooth LE, read-only.
ESP32 · CAN/TWAI
BLE FFF0/FFF1/FFF2
BLE FFF0/FFF1/FFF2
08 · Who it’s for
From the curious driver to the connected workshop.
Drivers
Understand a warning light before going to the garage, and arrive with a clear file.
Garages and workshops
A fast first diagnosis, logged per vehicle, that the customer can read back.
Fleets and rentals
A history per vehicle, readings comparable from one visit to the next.
AI integrators
An MCP probe ready to plug into your agents, with controlled permissions.
09 · FAQ
What people ask us.
Is the app on the App Store and Google Play?
Not yet. CENNTIR CAR is a pilot release (Android 0.6.1, iPhone 0.6) and in-vehicle trials are under way. Access is on request.
Will it work on my car?
If it has an OBD2 port, generic engine and emissions reading is possible. The data actually available varies by model. Manufacturer-specific control units (ABS, airbag, comfort…) are not covered at this stage.
Do I need a subscription or an AI key?
No. Local readings work without an account, hub or AI. For control by your assistant, the assistant connects to the probe through the CENNTIR hub: the app never asks you for a key.
Can I turn off the check-engine light?
Yes, from the phone only, after two confirmations. But clearing a code repairs nothing: if the cause remains, the light will come back. CENNTIR CAR helps you understand first.
Which adapter should I buy?
A Bluetooth LE ELM327 adapter works on both Android and iPhone (FFF0/FFE0 profiles, OBDLink CX). On Android, Bluetooth Classic models work too.
Where does my data go?
It stays on your phone. It only goes through the hub if you enable it, and only to the assistant you have authorised.
Your car has things to say. Let’s listen together.
We are opening CENNTIR CAR to a small number of drivers, workshops and fleets. Tell us about your use case.
10 · Pilot access
Try CENNTIR CAR on your own car.
Tell us who you are and what you drive: we will get back to you with the app, the recommended adapter and a first test run.
- Android or iPhone: guided installation of the pilot release.
- Recommended adapter for your phone and your car.
- Direct line to the team: your trials shape the next releases.