Phone-native diagnostics. No dongle required.

Your car's
black box,
finally readable

Point your phone at a check engine light. NexusCode reads every code, rates the severity, and explains exactly what it means — in plain English.

40+ Systems scanned
P0–U3 All code ranges
0ms Lag to clarity
SCANNING...
P0301 Cylinder 1 misfire detected
P0420 Catalyst system — below threshold
Severity
Monitor
O2 Sensor — Bank 1 Sensor 2
Cat efficiency below threshold
Fuel trims within spec
See how it works

Built for the person
who doesn't have a mechanic on speed dial

Instant code reads

Every diagnostic trouble code — P0 through U3, OEM-specific, ABS, airbag, transmission, ADAS — decoded in under a second. No cryptic hex. No guessing.

Severity first

Every code ranked Safe / Monitor / Urgent / Critical. Know immediately whether you're looking at a loose gas cap or a towed-home situation.

Live sensor data

Real-time fuel trims, O2 sensor readings, coolant temp, RPM, MAF flow. See what the sensor actually saw at the moment the code triggered.

Predicted failures

Using telemetry patterns from millions of vehicles, NexusCode forecasts what will fail next. Catch it before it leaves you stranded.

Parts & pricing

Instant parts lookup — OEM, aftermarket, 3D-printable. Live pricing, local availability, and links to order. One tap from diagnosis to checkout.

EV & hybrid ready

Battery state-of-charge, thermal drift, pack health, BMS logs. The diagnostic gaps that existing tools ignore — NexusCode covers.

Scan in seconds.
Understand in minutes.

No subscription. No dongle. No mechanic on call. Just your phone and every answer about your car, distilled into language anyone can act on.

01

Open the app

Point your phone at the dashboard. NexusCode detects the wireless OBD-II signal automatically — no pairing, no Bluetooth, no dongle.

02

Read every code

All DTCs, system by system. Engine, transmission, ABS, airbag, EV battery — full depth scan in under 10 seconds.

03

Know what to do

Plain-English explanation of what triggered each code, how serious it is, and the fastest path to a fix — DIY or pro.

Full System Diagnostic 12.4s
Engine Control OK
Transmission 2 codes
ABS / Brakes OK
Airbag / SRS OK
EV Battery (BMS) OK
Emissions / O2 1 code

Not just what.
Why and for how long.

URGENT P0301 — Cylinder 1 Misfire

Cylinder 1 isn't firing consistently. Most common cause at this mileage: worn spark plug. Could also be a bad ignition coil or fuel injector.

Risk Can damage catalytic converter if ignored
DIY? Yes — spark plug replacement is straightforward
Est. cost $8–45 in parts (DIY) / $150–300 at shop
Drivable Short distance — get it fixed within 500 miles
MONITOR P0420 — Catalyst System Efficiency

The catalytic converter isn't cleaning exhaust as efficiently as expected. 9 times out of 10 at this mileage, it's the downstream O2 sensor — not the cat.

Risk Low — emissions system only, not safety-critical
DIY? Possible — O2 sensor is accessible on most vehicles
Est. cost $25–120 (sensor) / $400–1200 (cat — unlikely needed)
Drivable Yes — monitor for 1–2 weeks before diagnosing

"The check engine light has been telling you something for years. You just didn't speak its language."

NexusCode is built for the 200 million vehicles on US roads over 12 years old — the ones dealers make the most money off because you don't know what's actually wrong. We fix that.

$89 Average shop diagnostic fee you avoid
12.8 Average age of US vehicles (2025) — the diagnostic sweet spot
73% Of check engine codes are fixable by the vehicle owner

Your car is trying to tell you something.
Let's make sure you're listening.

No subscription. No dongle. No mystery. NexusCode turns your phone into the most capable diagnostic tool you'll ever hold — and it fits in your glove box.

Start Scan — It's Free
Available on iOS and Android
Wireless OBD-II scan · No subscription · Free tier available