Lesson 1Engine coolant temperature and air intake temperature: impact on fueling and emissions control behaviorLearn how coolant and intake air heat affect fueling, timing, and smoke plans. Get warm-up ways, sensor check sense, and how wrong reads cause hard starts, smoke, or bad regen control.
Cold start temperature expectationsECT vs IAT plausibility comparisonTemperature effects on injection timingImpact on EGR and DPF strategiesDetecting biased or stuck temp sensorsLesson 2Intake manifold pressure and ambient pressure: expected values at idle and under load, and relationships to boostStudy intake manifold and outside pressure data to check boost system work. Learn normal idle and load values, height effects, and how to use pressure links to spot boost leaks, stuck turbos, or wrong MAP sensors.
Ambient pressure and altitude effectsExpected MAP at key load pointsUsing KOEO readings for sensor checksPatterns indicating boost leaksDetecting MAP sensor bias or driftLesson 3Exhaust Back Pressure (or DPF differential pressure): expected ranges, regeneration triggers, and signs of restrictionLearn to read exhaust back pressure and DPF diff pressure PIDs. Get normal ranges at idle and load, how regen changes reads, and how rising pressure shows exhaust blocks or bad DPF systems.
Normal back pressure at idle and loadDPF differential pressure thresholdsPressure behavior during regenerationIdentifying exhaust restrictions upstreamSensor and hose fault differentiationLesson 4Mass Air Flow (MAF) or Intake Air Mass: expected ranges, sensor response to throttle changes, and impact on fuelingLook at how to read MAF or figured air mass under different loads. Learn normal ranges, answer to throttle shifts, and how air flow data works with EGR and boost to guide right fueling and smoke check.
Baseline MAF at idle and no-loadMAF response to snap throttle testsMAF changes with EGR on and offUsing MAF to confirm boost deliveryDetecting contaminated MAF sensorsLesson 5Fuel rail pressure sensor voltage/PID and rail pressure demand vs actual comparisonGet how to read rail pressure sensor voltage and pressure PIDs, and match ordered versus real values. Learn to spot slow answer, overshoot, and low-pressure times that show pump, regulator, leak, or sensor troubles.
Typical rail pressure at idle and WOTSensor voltage to pressure relationshipCommanded vs actual pressure graphsDiagnosing slow pressure responseIdentifying leaks and relief valve issuesLesson 6EGR position and flow indicators: typical position ranges, response to commands, and symptoms of EGR faultsGet how to read EGR position and flow data, match ordered versus real values, and spot slow or stuck answers. Learn how EGR breaks affect drive ease, smoke, and how to split EGR issues from boost or air flow problems.
Typical EGR position ranges by loadCommanded vs actual EGR correlationSymptoms of stuck-open EGR valvesSymptoms of stuck-closed EGR valvesUsing MAF and MAP to confirm EGR flowLesson 7Injector correction/individual cylinder trim: normal small trims, large corrections indicating injector/ECU/pressure issuesLearn how injector fix values show cylinder balance, fueling rightness, and burn quality. Get normal trim ranges, when big changes worry, and how to link patterns to mechanical, electric, or ECU faults.
Normal trim ranges at idle and cruiseInterpreting positive vs negative trimsPatterns indicating faulty injectorsDistinguishing ECU vs mechanical issuesEffects of rail pressure errors on trimsLesson 8Engine RPM, throttle position, and accelerator pedal position: correlation checks and drive-by-wire sanityLook at how RPM, throttle spot, and pedal signals work in drive-by-wire setups. Learn to find match faults, dead spots, and delay that cause wait, limp mode, or unsafe speed-up on road tests.
Expected idle and cruise RPM valuesDual-track pedal sensor agreementThrottle plate vs pedal position trackingDetecting signal dropouts and noiseDrive-by-wire faults causing limp modeLesson 9Turbo boost pressure and wastegate control: expected boost curves, lag under load, and diagnosing boost leaksGet turbo boost pressure and wastegate or VGT control data. Learn normal boost curves, okay lag, and how to use scan tool graphs to split boost leaks, stuck movers, and control issues from real engine load troubles.
Target vs actual boost comparisonAcceptable turbo lag characteristicsUsing actuator command PIDsPatterns of boost leaks under loadOverboost and underboost fault cluesLesson 10Fuel temperature and fuel temperature sensor behavior: why it matters for fueling compensation and expected rangesLearn why fuel heat is watched, how it affects density and fix, and what ranges are usual. Get sensor ways during hot soak, re-circle, and how odd reads can mislead rail pressure and amount control.
Normal fuel temperature operating rangeHot soak and recirculation effectsFuel temp influence on density modelsInteraction with rail pressure controlIdentifying faulty temp sensor signalsLesson 11High-pressure rail pressure: normal ranges, expected behaviors under load, and signs of low rail pressure issuesStudy high-pressure rail ways across work states. Learn normal pressure ranges, ramp-up times, and steadiness under load, and how changes point to worn pumps, injector leaks, control valve breaks, or supply side troubles.
Pressure ramp-up during crankingStability at idle and steady cruisePressure response to rapid load stepsSigns of internal injector leakagePump wear vs suction restriction cluesLesson 12Battery voltage and crank/charge system parameters: effects on high-pressure pump and injector driver performanceGet how battery voltage and charge data affect high-pressure pump out and injector drivers. Learn to check crank voltage, alternator rule, and how low voltage can look like fuel or sensor faults in checks.
Minimum cranking voltage thresholdsStarter current draw and RPM impactAlternator output and load responseVoltage sensitivity of injector driversLow-voltage induced false DTCs
