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.

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P2022 Code Intake Runner Position Sensor Circuit High Bank 2DTC P24B0 Code Particulate Matter Sensor Circuit Low VoltageDTC P0610 Code Control Module Vehicle Options ErrorDTC P203E Code Reductant Level Sensor Intermittent or ErraticDTC P2320 Code Diagnose Ignition Coil G Secondary CircuitDTC P0942 Code Diagnose the Hydraulic Pressure UnitDTC P0864 Code Test the TCM Network SignalDTC P0028 Code Diagnose Bank 2 Intake Valve Control PerformanceDTC P0625 Code Generator Field/F Circuit LowDTC P0850 Code Park/Neutral Switch Input CircuitDTC P0502 Code Test Vehicle Speed Sensor A Circuit LowDTC P0142 Code Test the Bank 1 Sensor 3 O2 CircuitDTC P3000 Code Toyota Prius 123 and Battery ECU FaultsDTC P2651 Code Rocker Arm B Performance or Stuck OffDTC P2413 Code Diagnose EGR System PerformanceDTC P0556 Code Brake Booster Sensor PerformanceDTC P24AE Code Diagnose the Particulate Matter Sensor CircuitDiesel Aftertreatment P2682 Code Test Coolant Bypass Valve Control Circuit LowCooling System P2637 Code Diagnose Torque Management Feedback Signal ADTC P065B Code Generator Control Circuit Range / PerformanceDTC P0599 Code Test the Thermostat Heater Circuit HighCooling System P00FE Code Diagnose a Restricted EVAP Vapor LineDTC P2146 Code Test Injector Group A Supply Circuit OpenDTC P065A Code Diagnose Generator System PerformanceCharging System P0897 Code Transmission Fluid DeterioratedDTC P2280 Code Air Filter to MAF Restriction or LeakDTC P0322 Code Engine Speed Input Circuit No SignalDTC P0344 Code Camshaft Sensor A Circuit IntermittentDTC P013F Code Delayed Lean-to-Rich Response, Bank 1 Sensor 2DTC P0784 Code 4-5 Shift DiagnosisDTC P0370 Code High-Resolution Timing Signal ADTC P066D Code Cylinder 2 Glow Control Circuit HighDTC P2291 Code Injector Control Pressure Low During CrankingDTC P2230 Code Intermittent BARO Sensor A SignalDTC P0027 Code Exhaust Valve Control Performance, Bank 1DTC P013E Code Delayed Rich-to-Lean O2 Response, Bank 1 Sensor 2DTC P0611 Code Fuel Injector Control Module PerformanceDTC P3425 Code Cylinder 4 Deactivation Control Circuit/OpenDTC P24A5 Code EGR Cooler Bypass Control Stuck, Bank 1DTC P0542 Code Intake Air Heater A Circuit HighDTC P049D Code EGR A Position Exceeded Learning LimitDTC P011A Code Coolant Temperature Sensor 1/2 CorrelationDTC P2183 Code Coolant Temperature Sensor 2 PerformanceDTC P02E8 Code Diesel Intake Position Sensor Circuit LowDTC P00BC Code MAF A Airflow Too Low DiagnosisDTC P2200 Code NOx Sensor Circuit Bank 1 DiagnosisDTC P064C Code Glow Plug Control Module DiagnosisDTC P0281 Code Cylinder 7 Contribution and BalanceDTC P2652 Code Rocker Arm System B Stuck On, Bank 1DTC P0076 Code Intake Valve Control Circuit Low, Bank 1DTC
839 codes · page 3 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 →