Powertrain

Subsystems

• P00xx 252 Fuel and Air Metering, Auxiliary Emission Controls Measurement of what enters the engine and control of what leaves it: oxygen sensors, mass air flow, and the emission devices that depend on their readings.
• P01xx 253 Fuel and Air Metering Mixture control proper — fuel trim, intake air temperature, and the sensors feeding the fuelling calculation.
• P02xx 255 Fuel and Air Metering — Injector Circuit The injector drivers and their wiring, addressed per cylinder.
• P03xx 234 Ignition System or Misfire Spark delivery and combustion quality, including the per-cylinder misfire counters and the crankshaft position signal they are measured against.
• P04xx 242 Auxiliary Emission Controls Catalytic converters, EGR, evaporative emissions and secondary air — the systems that clean up combustion after the fact.
• P05xx 242 Vehicle Speed Control, Idle Control, Auxiliary Inputs Idle air control, cruise control, brake and clutch switches, and the vehicle speed signal.
• P06xx 248 Computer Output Circuits and Control Module Faults the control module raises about itself or its own output drivers — internal memory, processor and reference voltage problems.
• P07xx 249 Transmission Gear ratio monitoring, shift solenoids and torque converter clutch control.
• P08xx 229 Transmission (continued) Further transmission control: range sensing, shift timing and clutch actuation.
• P09xx 147 Transmission and Control Modules Transmission control module faults and the auxiliary modules that share responsibility for shifting.
• P0Axx 256 Hybrid Propulsion Drive motors, generators, and the high-voltage battery pack and its management.
• P0Bxx 256 Hybrid Propulsion (continued) Hybrid cooling, power inverters and converter control.
• P0Cxx 256 Hybrid Propulsion (extended) Extended hybrid and electric propulsion faults, including charging system control.
• P0Dxx 256 Battery Charging and Cell Balancing The on-board charger, the charging coupler and its lock, cell balancing, and the electric air conditioning compressor.
• P0Exx 255 Electrified Powertrain Auxiliaries The supporting systems of an electric powertrain: the DC/DC converter that replaces the alternator, battery thermal management, the generator inverter, climate control and the charging hardware. It is also where the standard placed the second and third instances of parts first enumerated in the earlier hybrid blocks — a Sensor B, a Converter B, a fifth battery pack — so a code here often has an older sibling hundreds of numbers away.
• P20xx 256 Fuel and Air Metering, Emission Aftertreatment Injector and fuel composition faults alongside the aftertreatment devices fitted after P0xxx was drawn up — NOx adsorbers, reductant injection and the sensors that police them.
• P21xx 252 Throttle Actuator Control and Oxygen Sensors Electronic throttle control — the motor, its position feedback and the redundancy around it — plus the oxygen sensor signal faults that describe a sensor stuck rather than absent.
• P22xx 256 Oxygen Sensor Control and Forced Induction Wide-band oxygen sensor current control, and the boost control detail that P0xxx covers only broadly: vane position, wastegate travel and charge air cooling.
• P23xx 182 Ignition, EGR and Glow Plug Control Ignition coil control detail, exhaust gas recirculation beyond the P04xx range, and per-cylinder glow plug monitoring.
• P24xx 255 Particulate Filter and Exhaust Aftertreatment Diesel particulate filters, their differential pressure and temperature sensors, and the regeneration process that keeps them clear. The range that matters most on a modern diesel.
• P25xx 217 Auxiliary Inputs, Ventilation and Engine Controls Crankcase ventilation, engine oil level and condition, auxiliary emission controls and the miscellaneous inputs that did not fit the earlier ranges.
• P26xx 234 Turbocharger, Cooling and Injector Control Turbocharger boost and speed detail, cooling system control, and the injector correction and balance faults that diagnose a common-rail engine cylinder by cylinder.
• P27xx 242 Transmission Hydraulics, Sensing and Actuation The transmission block of the P2 range: the pressure control solenoids that apply each clutch and band, the fluid temperature and shaft speed sensors that supervise them, the friction elements themselves, gear selection and range control, the park pawl, and the electric pumps that keep pressure up on a transmission whose engine stops at every junction. Where P0700 onward names the classic automatic, this range is where the standard put the detail — second and third solenoids, per-element timing and temperature, and the actuation of automated manuals.
• P28xx 192 Dual Clutch, Shift Actuation and Ion Sensing The second transmission block of the P2 range, and mostly the automated gearbox's internals: the shift forks that slide gears into mesh and the sensors watching them, per-clutch pressure and engagement timing for dual-clutch boxes, pressure control solenoids G through K, the second range sensor, the park lock actuator, and the clutch a hybrid uses to disconnect its engine entirely. The standard also filed cylinder ion current sensing — measuring combustion through the spark plug — into this block, an allocation that has nothing to do with gearboxes and sits here because this is where the numbers were free.
• P2Axx 256 Engine Management Extensions The block the standard came back to when the earlier P2 ranges filled up. It is deliberately broad — fuel system detail, further oxygen sensor faults, injection pump metering, exhaust aftertreatment, cooling and the starter relays — and much of it is the second or third instance of a part enumerated elsewhere, so a code here often has an older sibling in another range.
• P2Bxx 225 Injection Balance, Thermal Management and NOx Inducement A late block with six unrelated tenants: the per-cylinder injection pulse corrections that keep a modern engine's cylinders identical and the learned offsets behind them, the hybrid's electronics-coolant thermometers and battery coolant pump, the motorised coolant flow control valve that replaced the wax thermostat, the NOx exceedence codes through which diesel emissions law escalates from warning to torque limit to refusal to restart, and the alternative fuel system's consumption checks. What unites them is only that the standard reached this range late, when the earlier blocks were full.
• P2Cxx 67 Ignition Supply, Crankcase and Converter Thermal Barely opened, and only through manufacturer bulletins: the fuses feeding ignition coil primaries, crankcase pressure sensing and the hoses whose disconnection it detects, and temperature sensing inside the DC/DC converter. The rest of the block is assigned by the standard and documented nowhere public.
• P2Dxx 24 Cold Start Strategy What an engine does differently while it is still cold, when the catalyst is below working temperature and most of a journey's emissions are produced: intake manifold runner control and boost strategy specific to warm-up. Like P2Cxx, almost none of it is documented outside manufacturer bulletins.
• P2Exx 21 Shift-by-Wire, Drive Motor Current and Charging Gear selection sensing on a car with no mechanical linkage to the gearbox, the phase and excitation current sensors inside a drive motor, and the on-board battery charger. Most of it continues a family that starts hundreds of numbers earlier.
• P34xx 117 Cylinder Deactivation and Camshaft Actuator Control Cylinder deactivation — the intake and exhaust valve control circuits that shut individual cylinders down to save fuel under light load — enumerated per cylinder and per bank, followed by the camshaft position actuators and the temperature and position sensors that supervise them. Both families are about holding a valve away from the motion the crankshaft is asking for, which is why one range carries them.