Short answer: ARIA accesses everything available through the OBD-II standard — trouble codes, live sensor data, emissions monitors, and vehicle identification. Some systems (body electronics, ABS, airbags) use different modules outside OBD-II scope and require manufacturer-specific tools. However, ARIA often finds patterns in OBD-II data that reveal problems in seemingly unrelated systems.
What’s Inside OBD-II Scope
The OBD-II standard covers emissions-related powertrain systems:
Full Access
- Diagnostic Trouble Codes — Stored, pending, and permanent
- Live Sensor Data — RPM, speed, temperatures, fuel trims, O2 sensors, throttle position, MAP, MAF, timing, and dozens more
- Emissions Monitors — Readiness status for all supported monitors
- Vehicle Identification — VIN, calibration IDs, ECU names
- Freeze Frame Data — Conditions when a fault was detected
- Mode 6 Test Results — Raw pass/fail data from monitoring tests (where supported)
Partial Access (Varies by Vehicle)
- Transmission Codes — Generic P07xx codes accessible; manufacturer-specific codes may or may not appear
- Enhanced PIDs — Some manufacturers expose more data than required
What’s Outside OBD-II Scope
These systems use different control modules and communication protocols:
Body Electronics (BCM)
- Power windows, locks, mirrors
- HVAC and climate control
- Seat heaters and adjusters
- Interior/exterior lighting
- Infotainment and audio
Chassis Systems
- ABS (some newer vehicles expose partial data)
- Stability control (ESC/VSC)
- Active suspension
- Electronic power steering
Safety Systems
- Airbag module (SRS)
- Seatbelt pretensioners
- Crash sensors
Security Systems
- Immobilizer
- Key fob programming
- Anti-theft module
These require manufacturer-specific tools (GM Tech2, Ford IDS, Toyota Techstream, etc.).
What ARIA Can Still Find
Many problems show up in OBD-II data even when they seem unrelated:
| Problem | How ARIA Detects It |
|---|---|
| Failing alternator | Voltage readings dropping under load |
| Slipping transmission | RPM vs. speed discrepancies |
| Clogged catalyst | Oxygen sensor switching patterns |
| Vacuum leaks | Fuel trim compensation patterns |
| Ignition misfires | Individual cylinder misfire counts |
| Weak fuel pump | Fuel pressure PID (if supported) |
| Cooling system issues | Temperature sensor relationships |
ARIA analyzes relationships between sensor readings that reveal problems even without explicit trouble codes.
Manufacturer Variability
Beyond the OBD-II baseline:
- Some manufacturers expose extensive data
- Others lock down everything except emissions minimums
- Data access varies by model year and market region
ARIA accesses the full OBD-II standard plus enhanced modes where the vehicle supports them.
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Questions? support@obdai.app