P CODE FAMILY

Powertrain code references — Page 14.

Engine, transmission and powertrain diagnostic references. Exact vehicle and module context still matters.

Generic OBD-II

P0518

These are code references, not a list of confirmed faults on every vehicle. Read the source and applicability notes, then match the exact vehicle, year, engine and scan report.

Idle Air Control Circuit Intermittent

Idle Air Control System Performance

A digital crankcase-pressure sensor fault is not a PCV hose diagnosis

Crankcase-pressure rationality can fail without an electrical extreme

Low crankcase-pressure sensor voltage is an analog circuit result

High crankcase-pressure sensor voltage does not prove high physical pressure

Crankcase Pressure Sensor A Circuit Intermittent/Erratic

PCV Filter Restriction

Distinguish a digital oil-pressure fault from an analog voltage limit

Oil-pressure plausibility depends on pump stage and operating state

Oil-pressure sensor output below its reference-relative range

Oil-pressure sensor high output needs electrical validation

Low oil-pressure detection uses a mapped limit and debounce

Cruise Control Servo Control Circuit Range/Performance

A nearly absent fan-speed signal needs a valid speed expectation

Fan Speed Sensor Circuit Range/Performance

Fan Speed Sensor Circuit No Signal

Fan Speed Sensor Circuit Intermittent

Cold-start bank 1 cam advance has a short diagnostic window

Bank 1 cold-start retard error needs the original command history

Bank 2 over-advance during cold start is a bank-specific response result

Cold-start bank 2 retard error can disappear before inspection

PCV malfunction can involve a leaking breather elbow

the glow-control module reports an implausible supply value

Jeep diesel A/C pressure diagnosis includes the reference supply

A/C pressure response can fail while voltage stays in range

A/C pressure-sensor low voltage is an electrical result

A/C pressure feedback is near the high electrical limit

hybrid cooling performance can fail for more than low charge

A/C Evaporator Temperature Sensor Circuit

A/C Evaporator Temperature Sensor Circuit Range/Performance

evaporator temperature sensor voltage persistently low

evaporator sensor voltage high from an open or power short

evaporator temperature signal changes too quickly

PCV Heater A Control Circuit /Open

Crankcase heater supply remains low when its relay is commanded on

Crankcase heater voltage stays high after the relay is switched off

PCV Heater A Performance

Crankcase Pressure Too High

Cold-start fuel pressure is evaluated across the emission-reduction period

Intake Air Heater A Circuit

Intake Air Heater A Circuit Low

Intake Air Heater A Circuit High

Intake Air Heater A Circuit Open

An exhaust-temperature circuit code can be a model-rationality result

EGT sensor 1 low-range feedback and a source limitation

EGT sensor 1 above its raw electrical range

Bank2 exhaust-temperature plausibility needs the correct operating window

Bank2 low EGT voltage is an electrical threshold, not cold exhaust proof

A high EGT circuit reading has an explicit warm-up qualification

Cold Start B Camshaft Position Timing Over-Advanced Bank 1

Cold Start B Camshaft Position Timing Over-Retarded Bank 1

Cold Start B Camshaft Position Timing Over-Advanced Bank 2

Cold Start B Camshaft Position Timing Over-Retarded Bank 2

idle torque-forming fuel quantity below its mapped expectation

idle injection quantity above the selected maximum map

Titan steering-pressure feedback and idle compensation

implausible power-steering pressure switch feedback

Power Steering Pressure Sensor/Switch Circuit Low

Power Steering Pressure Sensor/Switch Circuit High

Power Steering Pressure Sensor/Switch Circuit Intermittent

Brake booster vacuum sensor signal outside its electrical range

Brake-booster pressure plausibility uses several comparisons

Low brake-booster pressure sensor voltage

High booster-pressure sensor voltage needs electrical interpretation

Brake Booster Pressure Sensor Circuit Intermittent

Engine Oil Pressure Sensor/Switch B Circuit

Engine Oil Pressure Sensor/Switch B Range/Performance

Engine Oil Pressure Sensor/Switch B Low

Engine Oil Pressure Sensor/Switch B High

Oxygen Sensor Control Module System Voltage

Excessive oil pressure is separate from an implausible sensor signal

Honda ECM backup supply loses voltage

compare the TCM battery feed with its ignition feed

Low system voltage measured while the engine is turning

High 12-volt system voltage in the ECM monitor

Cruise switch voltage falls between valid command ranges

Momentary cruise on/off input remains applied too long

Cruise Control Off Signal

Cruise resume remains decoded as applied