Windows fogging on the inside: where the water is coming from
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OBD-II · AI · Cloud
Car Diagnostics Platform
On-board OBD-II diagnostics with cloud analytics, AI assistant and fleet support.
Check car compatibilityBlog
Articles on diagnostics, OBD-II and car maintenance
P0404: EGR position sensor range/performance explained
P0404 compares commanded EGR position against measured position. Carbon, not electronics, is behind most of them — and cleaning beats replacing far more often than parts sellers admit.
How the EVAP monitor tests for leaks, and why it needs half a tank
The fussiest test on the car. Knowing its conditions is the difference between a week of aimless driving and a readiness status that completes.
OBD codes and the emissions test: what actually fails you
Most emissions-test failures on modern cars are not about exhaust gas at all. They are about the lamp being lit and the monitors not being ready — both checkable in your driveway.
Fluctuating Idle RPM: 10 Causes and How to Diagnose via OBD-II
Idle rpm not stable — swings between 700 and 1200: how to identify the cause in 10 minutes — MAF, IAC, EGR, injectors, vacuum leak.
SAE J1979-2 (OBDonUDS): why your scanner suddenly reads less
A newer car that returns fewer parameters than an older one is not faulty and your adapter is not broken. The legislated data moved to a different protocol.
SEAT Leon and Ateca: OBD diagnostics and VAG shared parts
Mechanically these are Golfs and Tiguans with different bodywork, which means every fault is already documented under another badge. Here is what transfers and what does not.
P0301-P0304: misfire on a specific cylinder and how to localise it
A cylinder-specific misfire code hands you the location for free. The swap test then tells you whether the fault travels with the part or stays with the cylinder.
Revs hang between shifts: emissions calibration, not a fault
Lift off to change gear and the revs stay up for a moment before falling. Almost every modern manual does it, and the reason is not what most people assume.
P0251: injection pump fuel metering control on a diesel
The metering valve decides how much fuel the high pressure pump takes in. When it stops obeying, the whole rail pressure loop loses its main lever.
Isuzu D-Max and SsangYong/KGM: diesel OBD diagnostics
Working diesels bought for towing and load carrying. The emissions hardware is the recurring cost, and the drivetrain oils are the recurring omission.
Check Engine flashing vs steady: the difference that decides whether you keep driving
A steady lamp says "book a diagnostic soon". A flashing lamp says "stop now". They are two distinct signals from one indicator, and confusing them costs a catalytic converter.
What our users actually find
Check Engine on for 2 months
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Before: shop wanted $400 to replace the catalytic converter.
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After: scanned → P0420. Turned out to be a $15 oxygen sensor. Light stayed off.
Diesel lost power
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Before: no idea whether it's the DPF, EGR or an injector. Shop suggested "full diagnostics" for $180.
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After: P0401 — insufficient EGR flow. Cleaned the valve at home, power returned.
Battery drained every morning
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Before: a new battery didn't help. Electrician muttered about "wiring issues".
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After: U0140 — lost communication with BCM. Corroded terminals; cleaned them, problem solved.
Rough idle on a Corolla
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Before: mechanic suggested a full engine overhaul. Vibration at idle, no clear cause.
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After: P0303 — misfire on cylinder 3. Replaced one spark plug for $4. Idle smooth again.
Fuel consumption doubled
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Before: replaced filters, O2 sensor, injectors — nothing helped. Burning 14 L/100 km.
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After: P0171 — lean mixture, MAF out of range. Cleaned the sensor — dropped to 8 L/100 km.
Automatic jerked on 2nd gear
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Before: shop quoted a $900 transmission rebuild. Symptoms: jolts during acceleration.
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After: P0715 — turbine speed sensor. $35 part, 30-minute job. Jerking gone completely.
Engine overheated on the highway
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Before: replaced the radiator and coolant — temperature still crept up on long drives.
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After: P0128 — thermostat stuck open. $18 replacement fixed it; temp stays normal.
Fuel smell inside the cabin
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Before: mechanics shrugged. One suggested replacing the fuel tank — $400.
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After: P0456 — small EVAP leak. A cracked $6 nipple was the culprit. Smell gone.
ABS triggered on dry pavement
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Before: brakes checked twice — everything fine. ABS still kicked in randomly.
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After: C0035 — front left wheel speed sensor faulty. $22 replacement, no more false ABS.
Wouldn't start after rain
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Before: cranked fine but no start every rainy day. New plugs and coil did not help.
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After: P0335 — crankshaft position sensor with damaged insulation. $28 fix, starts every time.
Engine hesitated during overtake
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Before: tuning shop offered an ECU remap for $220. Power fell off sharply at 3000 rpm.
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After: P0101 — MAF out of range. $45 sensor swap. Acceleration became smooth and strong.
AC stopped cooling
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Before: recharged refrigerant 3 times in one summer — $120 wasted, lasted a week each time.
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After: P0530 — AC pressure sensor faulty. $16 part, no more leak, cold air all summer.
Sample scenarios based on common cases — real customer quotes will appear once we collect publication consent.
Saw a trouble code on your dashboard?
Enter the DTC and find out what it means, how severe it is and what causes it.
View all 150 popular codesOne platform, three use cases
DIY driver
You own the car and want to know what "Check Engine" means before the shop. Quick sessions from the phone, per-car history, plain-language AI explanations.
Personal tierShop mechanic
You own or work in a small garage. Web panel with concurrent sessions, branded PDF reports for customers, DTC library with explanations.
Pro tierFleet manager
You run 10 to 500+ vehicles. Roles and permissions, automatic alerts on critical DTCs, cross-vehicle comparison, exportable reports.
Fleet tierThe whole story on one screen
DTC + plain-English explanation
Why the light came on, how serious it is, and what to do next — no jargon.
Live telemetry
RPM, coolant temp, MAF, throttle — in real time, like a factory service manual.
AI assistant
Describe the symptom — the model cross-checks ECU data and suggests the likely cause.
How much you'll save per year
Shop diagnostic visits
$60 – $120 × 2–3 times/year
≈ $180 – $360
App + ELM327 adapter (one-off)
≈ $10 (adapter) + subscription from $3/month
≈ $46 / year
Difference
≈ $130 – $310 per year
Estimate for a single-car driver who deals with 2–3 unexplained warnings a year. Your savings depend on how often things go wrong.
Will your car work?
OBD-II is mandatory on passenger cars (USA since 1996, EU since 2001) and on light commercial vehicles (since 2005).
Yes, your car is supported
You need an ELM327-based OBD-II adapter (Bluetooth Classic SPP) — from $10–15. Pair and start a session.
Limited support
Your car may use a non-standard OBD-II variant. Try it — the app auto-detects the protocol (ISO 15765, KWP2000, ISO 9141).
Not supported
Before 1996 (US) / 2001 (EU) cars used OBD-I with a different connector and protocol. OBD-I is not supported.
What AI diagnostics looks like on a real code
- 01
What the scan sees
DTC P0301 confirmed, live data shows a +12% Long-Term Fuel Trim spike on cylinder 1, brief misfires under load.
- 02
What the AI says
Most likely cause — cylinder 1 ignition coil (44%), then spark plug (28%). Injector — 15%, compression — 10%. Recommendation: swap the coil first; the AI predicts P0301 will clear within 3 cold starts.
- 03
What to do next
Coil ~$45, 20-min DIY or ~$30 labour at a shop. Vs. a $150 scan-and-guess shop diagnostic — getting the right part first saves time and money.
Illustrative example — real findings depend on your car.
How our AI diagnostics work
Specialized knowledge base
Approximately 145,000 DTC codes with expert descriptions, stored server-side — never bundled into the mobile app. The AI is grounded in this data rather than answering from general training knowledge.
RAG: retrieval-augmented generation
A dedicated retrieval service backed by a vector database with text embeddings. Relevant technical material is retrieved and injected into the model context before it answers — the model does not answer from its general training knowledge alone.
The model
A large commercial language model accessed through a model-routing abstraction layer, so the provider can be swapped without altering the diagnostic pipeline.
Thin client by design
The mobile app is an Apache Cordova shell with a React UI layer. The diagnostic session is server-owned: the phone acts as a transparent proxy, not the decision-maker. Logic lives once, server-side — auditable and upgradable without an app-store release cycle.
- 1900+ DTC codes explained
- 1996+ Years of OBD-II vehicles
- 8 AI agents for diagnostics
What we won't do
No ECU flashing without consent
We read parameters and DTCs (Mode 01, 03, 09) — passive queries only. Writing to the ECU only happens with explicit consent and a risk disclosure.
We recommend a shop when needed
When a code points to pressurized fuel systems, brakes or airbags, the AI plainly says "go to a shop" — instead of pushing DIY to keep you subscribed.
No fake urgency, no upsell scripts
No "3 seats left" or "special price today". The tier price is the same tomorrow as it is now.
Quick answers
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Do I need to buy anything besides the app?
Yes, an OBD-II adapter on the ELM327 chip (Bluetooth Classic SPP) — starts around $10. We do not sell adapters, but we maintain a compatibility list in the docs.
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Which vehicles are supported?
All cars and light commercial vehicles with an OBD-II port — mandatory since 1996 in the US, 2001 in the EU. Heavy trucks on J1939 are on the roadmap.
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Is connecting to the ECU safe?
Reading data (Mode 01, 03, 09) is fully safe — passive queries only. Clearing DTCs (Mode 04) is safe but requires explicit confirmation. We do not perform write operations without certification.