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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P0777 Code Pressure Control Solenoid B Stuck OnDTC P0045 Code Boost Control A Circuit/Open DiagnosisDTC P0017 Code Bank 1 Sensor B Cam-Crank CorrelationDTC P0989 Code Transmission Pressure Switch E Circuit LowDTC P2872 Code Clutch A Stuck Engaged DiagnosisDTC P088A Code Transmission Filter Deteriorated GuideDTC P010B Code MAF B Range / Performance DiagnosisDTC P0876 Code Pressure Sensor D Range / PerformanceDTC P0078 Code Bank 1 Exhaust Valve Control CircuitDTC P010C Code MAF B Circuit Low DiagnosisDTC P0678 Code Cylinder 8 Glow Plug Circuit DiagnosisDTC P0148 Code Fuel Delivery Error DiagnosisDTC P0096 Code Intake Air Temperature Sensor 2 PerformanceDTC P261B Code Coolant Pump B Control PerformanceDTC P2297 Code O2 Response During DecelerationDTC P000D Code Bank 2 B Camshaft Slow ResponseDTC P0986 Code Shift Solenoid E Circuit High DiagnosisDTC P2700 Code Friction Element A Apply Time DiagnosisDTC P0869 Code Transmission Fluid Pressure HighDTC P0643 Code Sensor Reference Voltage A Circuit HighDTC P2199 Code Intake Air Temperature Sensor CorrelationDTC P0914 Code Gear Shift Position Circuit DiagnosisDTC P2202 Code NOx Sensor Circuit Low Bank 1 Sensor 1Diesel Aftertreatment P0976 Code Shift Solenoid B Control Circuit LowDTC P0348 Code Camshaft Position Sensor A Circuit High Bank 2Camshaft Sensor P228B Code Fuel Regulator 2 Forced Engine ShutdownDTC P2602 Code Coolant Pump A Control Circuit LowCooling System P015A Code O2 Sensor Rich-to-Lean Delayed ResponseDTC P0765 Code Shift Solenoid D DiagnosisDTC P0047 Code Boost Control Solenoid Circuit LowDTC P00B4 Code Radiator Coolant Temperature Sensor Circuit HighDTC P2808 Code Pressure Control Solenoid G Performance/Stuck Off P2601 Code Coolant Pump A Performance/Stuck Off P0727 Code Engine Speed Input Circuit No Signal P014A Code O2 Sensor Delayed Rich-to-Lean Response P0350 Code Ignition Coil Primary/Secondary Circuit P2753 Code Transmission Fluid Cooler Control Circuit Open P2837 Code Shift Fork B Position Range/Performance P2542 Code Test the Low-Pressure Fuel Sensor High CircuitDTC P0775 Code Pressure Control Solenoid B Diagnosis P0147 Code O2 Sensor Heater Circuit (Bank 1 Sensor 3) P0552 Code Power Steering Pressure Sensor Circuit Low Input P0977 Code Test Shift Solenoid B Control Circuit HighDTC P2433 Code Test the Secondary Air Pressure Sensor High CircuitDTC P062D Code Test Fuel Injector Driver Performance Bank 1DTC P0313 Code Diagnose Misfire Detected With Low FuelDTC P2179 Code Diagnose System Too Lean Off Idle Bank 2DTC P000A Code A Camshaft Position Slow Response Bank 1 P0A43 Code Drive Motor A Position Sensor Circuit Intermittent P0778 Code Pressure Control Solenoid B Electrical
839 codes · page 4 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 →