Support · Fault Code Lookup

OBD-II Fault Code Guides

Mechanic-written repair guides for every trouble code — what it really means, what actually causes it, and how to fix it before you replace expensive parts.

Most searched
All
P0033 Code Turbocharger Bypass Valve Control Circuit P2294 Code Fuel Pressure Regulator 2 Control Circuit P2091 Code Exhaust Cam Actuator Circuit High P0145 Code O2 Sensor Slow Response B1S3 P2311 Code Ignition Coil D Secondary Circuit P0129 Code Barometric Pressure Too Low P246C Code DPF Restriction and Limited Power P0B25 Code Hybrid Battery A Voltage Low P0514 Code Battery Temperature Monitoring P0533 Code A/C Pressure Signal High P0485 Code Cooling Fan Power and Ground P0785 Code Shift Solenoid A Circuit Checks P2167 Code Throttle/Pedal E Maximum StopDTC P0873 Code Transmission Pressure C HighDTC P2600 Code Coolant Pump A Circuit/OpeniCARZONE P206A Code Reductant Quality Sensor CircuitDTC P245A Code EGR Cooler Bypass ControlDTC P0465 Code EVAP Purge Flow Sensor CircuitDTC P1962 Code Ferrari DCT Ground Loop 3DTC P0C17 Code Drive Motor Position Not LearnedDTC P0338 Code Crank Sensor A Circuit HighiCARZONE P0492 Code Secondary Air Flow, Bank 2DTC P0692 Code Fan 1 control circuit highDTC P0273 Code Cylinder 5 injector circuit lowDTC P0768 Code Shift solenoid D electricalDTC P0790 Code Normal/performance switch circuitDTC P0262 Code Cylinder 1 injector circuit highDTC P0469 Code Purge flow sensor circuit intermittentDTC P056E Code Cold Start Turbocharger Boost Control A PerformanceDTC P3439 Code Cylinder 5 Exhaust Valve Control Circuit LowDTC P0634 Code Control Module Internal Temperature Too HighDTC P0745 Code Pressure Control Solenoid A DiagnosisDTC P0658 Code Actuator Supply Voltage A Circuit LowDTC P0530 Code A/C Refrigerant Pressure Sensor CircuitDTC P1681 Code Identify the Manufacturer-Specific FaultDTC P073E Code Unable to Engage Reverse — Diagnose the CauseDTC P0963 Code Pressure Control Solenoid A Circuit HighDTC P0346 Code Bank 2 Camshaft Sensor Range/PerformanceDTC P0382 Code Glow Plug/Heater Circuit B MalfunctionDTC P0654 Code Engine RPM Output Circuit DiagnosisDTC P0761 Code Shift Solenoid C Performance or Stuck OffDTC P200E Code Catalyst System Over Temperature, Bank 1DTC P2711 Code Gear Disengages UnexpectedlyDTC P076F Code Gear 7 Incorrect Ratio DiagnosisDTC P2607 Code Intake Air Heater B Circuit LowDTC P2240 Code Bank 2 Sensor 1 Positive Current CircuitDTC P02E0 Code Diesel Intake Air Flow Control Circuit/OpenDTC P2159 Code Vehicle Speed Sensor B Range and PerformanceDTC P063C Code Generator Voltage Sense LowDTC P053A Code PCV Heater Circuit/OpenDTC
839 codes · page 1 of 17
01 Read your code

Every code is four signals in five characters.

P
System
P = Powertrain (engine & transmission)
0
Type
0 = generic SAE standard · 1 = make-specific
4
Subsystem
The subsystem the code points to
2
Fault
The specific fault
0
Index
Index within that subsystem
P
Powertrain

Engine, fuel, ignition, emissions and transmission. By far the most common — most check-engine lights start with P.

B
Body

Interior comfort and safety: airbags, lighting, power windows, seats, climate control.

C
Chassis

Mechanical systems outside the body: ABS, traction control, steering, suspension, wheel-speed sensors.

U
Network

Communication between control modules over the car's data bus (CAN). Often points to wiring or a module that has gone quiet.

Generic vs manufacturer-specific: a 0 in the second position means the code follows the SAE standard and means the same on every car — those are the ones in this library. A 1 (and sometimes 3) means the carmaker defined it themselves, so the same code can mean different things on a BMW and a Toyota. For those, read the exact definition on your scan tool.

02 When the light comes on

Four moves, in order.

  1. Is it flashing?

    A flashing check-engine light usually means an active misfire that can damage the catalytic converter — ease off the throttle and get it looked at promptly. A steady light is rarely an emergency; investigate soon.

  2. Scan for the codes

    Plug in a scan tool and read the stored codes. Note every code and its freeze-frame data — the first one set is often the root cause of the rest.

  3. Look it up

    Search the code here to understand what system it points to, how serious it is, and the parts most often behind it — before you spend a cent on parts.

  4. Fix, clear, confirm

    Repair the root cause, clear the code, then drive and re-scan. If it comes straight back, the underlying fault is still there — keep diagnosing, don't just keep clearing.

From code to cause

A code tells you the system. A scanner tells you the part.

Reading the code is step one. ICARZONE tools go further — live data, bidirectional actuator tests and OE-level access pinpoint the actual faulty component, then clear the code once it's fixed.

Explore the toolsCompare models

Can't find your code, or got a P1/B1/C1/U1 code? Those are manufacturer-specific. Tell our team the code and your vehicle (make, model, year) and we'll help you read it — or grab the exact OE definition with an ICARZONE tool. Contact support →