Diagnostic Library144 published faults

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Recently Updated Fault Codes

Engine oil pressure below normal operating range – moderately severe

DPF Differential Pressure - Signal Erratic

EGR differential pressure signal erratic – unstable flow feedback

Aftertreatment inducement active due to emissions fault – follow supporting codes

DPF regeneration too frequent due to soot source – condition exists

Battery voltage low – weak batteries, alternator, or poor connections

Battery voltage high – charging system overvoltage

DEF pump not responding – pump does not follow command

DEF pump motor current low / open circuit

DEF pump prime/pressure build fault – pressure not achieved

EGR differential pressure voltage low – open circuit/short to ground

Turbo actuator position low – signal lost / open circuit

Turbo actuator position erratic – VGT control instability

Aftertreatment diesel oxidation catalyst (DOC) performance condition exists

SCR dosing valve not responding – command not followed

SCR dosing valve current low / open circuit

SCR dosing rate too low – DEF not injected as expected

DPF ash load high – DPF service required

Boost pressure voltage low – open circuit/short to ground

Boost pressure voltage high – MAP/boost sensor circuit fault

Aftertreatment 1 inlet temperature too low – SCR not reaching operating range

Aftertreatment 1 outlet temperature too low during dosing

Aftertreatment outlet NOx sensor drift – SCR efficiency calculations unreliable

Aftertreatment 1 intake NOx sensor abnormal update rate

DPF soot load high – regen required soon

DPF regeneration inhibited due to conditions – regen will not initiate

Aftertreatment regen inhibited – operating conditions not met

Misfire monitor condition exists (rough running complaint)

DEF tank heater below normal (weak heating)

DEF dosing pressure data erratic (unstable signal)

DEF tank heater voltage low / short to ground

Engine protection torque derate active (follow the other codes)

Accelerator pedal channel 2 voltage high

DEF line heater relay voltage high / short to power

Engine throttle valve operation out of calibration

DPF regeneration too frequent (condition exists)

DEF doser valve not responding

DEF doser valve current low / open circuit

Engine throttle valve temperature status voltage low

Engine throttle valve temperature status voltage high

ECU supply voltage low (power/ground problem causing random faults)

DPF missing condition exists (hardware/config mismatch)

EGR cooler efficiency below normal (soot/regens increase)

SCR intake temperature signal erratic (sensor/connection)

DEF line heater 3 voltage low / short to ground

DEF line heater 2 voltage low / short to ground

DEF line heater 1 current low / open circuit

DEF dosing pressure not responding (system not responding)

DEF dosing pressure below normal (weak pump or restriction)

DEF dosing unit input lines condition exists (line/flow issue)

SCR conversion efficiency below normal (inducement risk)

DEF doser valve condition exists (sticking/crystallization)

DPF outlet pressure sensor voltage low – open circuit

Aftertreatment NOx catalyst inlet temp too high – catalyst stress

Aftertreatment outlet NOx sensor voltage low – poor NOx data

DEF quality sensor voltage below normal – incorrect DEF quality readings

DEF quality sensor voltage high – possible short to power

Intake NOx sensor circuit intermittent – data unstable

DPF outlet temp sensor data drift – readings not rational

DPF pressure sensor voltage high – possible power short

DPF pressure sensor voltage low – open circuit

Fuel rail pressure under capacity – injector enabling insufficient

Fuel rail pressure not reached – injection enabling failed

Crankcase pressure low – ventilation concern

Engine turbocharger boost pressure not responding – weak turbo

DPF intake pressure too high – soot accumulation

Air mass flow sensor voltage high – fuel mix errors

SCR catalyst system missing – condition exists

DPF intake gas temp erratic – sensor data noise

DPF intake gas temperature high – heated path fault

DPF outlet pressure sensor voltage above normal

DPF dosing temp sensor voltage high – soot burn temp anomaly

Turbocharger VGT nozzle stuck – weak boost and lag

EGR valve malfunction – mechanical fault exists

SCR outlet temperature sensor voltage high – heater circuit issue

SCR outlet temperature sensor voltage low – open circuit

Barometric pressure sensor voltage high – altitude reading error

NOx sensor rationality fault – sensor disagreeing with expected values