P CODE FAMILY
Powertrain code references — Page 65.
Engine, transmission and powertrain diagnostic references. Exact vehicle and module context still matters.
Generic OBD-II
P209F
Ram DEF-tank heater performance warning and DCU software
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Generic OBD-II
P20A0
reductant purge-driver feedback is wrong while commanded off
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Generic OBD-II
P20A1
reductant pressure-reduction performance needs its own test state
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Generic OBD-II
P20A2
low purge-valve feedback is evaluated with the driver off
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Generic OBD-II
P20A3
purge-driver feedback remains high during the on command
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Generic OBD-II
P20A4
Reductant Purge Control Valve A Stuck Open
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Generic OBD-II
P20A5
Reductant Purge Control Valve A Stuck Closed
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Generic OBD-II
P20A6
Reductant Injection Air Pressure Control Valve Circuit/Open
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Generic OBD-II
P20A7
Reductant Injection Air Pressure Control Valve Performance
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Generic OBD-II
P20A8
Reductant Injection Air Pressure Control Valve Circuit Low
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Generic OBD-II
P20A9
Reductant Injection Air Pressure Control Valve Circuit High
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Generic OBD-II
P20AA
Reductant Injection Air Pressure Control Valve Stuck Open
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Generic OBD-II
P20AB
Reductant Injection Air Pressure Control Valve Stuck Closed
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Generic OBD-II
P20AC
Reductant Metering Unit Temperature Sensor Circuit
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Generic OBD-II
P20AD
Reductant Metering Unit Temperature Sensor Circuit Range/Performance
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Generic OBD-II
P20AE
Reductant Metering Unit Temperature Sensor Circuit Low
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Generic OBD-II
P20AF
Reductant Metering Unit Temperature Sensor Circuit High
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Generic OBD-II
P20B0
Reductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic
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Generic OBD-II
P20B1
Reductant Heater Coolant Control Valve Circuit/Open
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Generic OBD-II
P20B2
Reductant Heater Coolant Control Valve Performance/Stuck Open
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Generic OBD-II
P20B3
Reductant Heater Coolant Control Valve Circuit Low
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Generic OBD-II
P20B4
Reductant Heater Coolant Control Valve Circuit High
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Generic OBD-II
P20B5
metering-unit heater conductance is checked during heating
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Generic OBD-II
P20B6
Reductant Metering Unit Heater Control Circuit Performance
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Generic OBD-II
P20B7
the metering-unit heater's low-conductance start check
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Generic OBD-II
P20B8
high metering-heater conductance is not high tank temperature
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Generic OBD-II
P20B9
How the first DEF tank heater is checked for an open circuit
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Generic OBD-II
P20BA
When DEF tank heater power or calculated resistance misses its target
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Generic OBD-II
P20BB
heater 1 ground-short classification uses an off-state test
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Generic OBD-II
P20BC
Understanding a high-circuit failure on DEF tank heater 1
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Generic OBD-II
P20BD
Why an open DEF line-heater circuit is distinct from a tank-heater fault
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Generic OBD-II
P20BE
line-heater performance checks resistance and delivered power
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Generic OBD-II
P20BF
Reading a DEF line-heater low-circuit diagnosis correctly
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Generic OBD-II
P20C0
A DEF line-heater short-to-power report and its diagnostic shutdown
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Generic OBD-II
P20C1
heater C maps to the second tank heater in this system
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Generic OBD-II
P20C2
Checking the second DEF tank heater’s resistance and power performance
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Generic OBD-II
P20C3
Locating the meaning of a low circuit on the second DEF tank heater
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Generic OBD-II
P20C4
heater 3 short-to-power is confirmed with heating switched off
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Generic OBD-II
P20C5
Reductant Heater D Control Circuit/Open
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Generic OBD-II
P20C6
Reductant Heater D Control Circuit Performance
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Generic OBD-II
P20C7
Reductant Heater D Control Circuit Low
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Generic OBD-II
P20C8
Reductant Heater D Control Circuit High
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Generic OBD-II
P20C9
Reductant Control Module Requested MIL Illumination
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Generic OBD-II
P20CA
Reductant Injection Air Pressure Leakage
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Generic OBD-II
P20CB
The exhaust fuel injector’s open check uses different driver states
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Generic OBD-II
P20CC
aftertreatment injector performance is judged through exhaust heat
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Generic OBD-II
P20CD
A low aftertreatment-injector circuit result has separate recovery logic
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Generic OBD-II
P20CE
A high exhaust injector circuit can be reported through on-state overcurrent
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Generic OBD-II
P20CF
Exhaust Aftertreatment Fuel Injector A Stuck Open
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Generic OBD-II
P20D0
Exhaust Aftertreatment Fuel Injector A Stuck Closed
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Generic OBD-II
P20D1
Exhaust Aftertreatment Fuel Injector B Control Circuit/Open
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Generic OBD-II
P20D2
Exhaust Aftertreatment Fuel Injector B Control Performance
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Generic OBD-II
P20D3
Exhaust Aftertreatment Fuel Injector B Control Circuit Low
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Generic OBD-II
P20D4
Exhaust Aftertreatment Fuel Injector B Control Circuit High
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Generic OBD-II
P20D5
Exhaust Aftertreatment Fuel Injector B Stuck Open
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Generic OBD-II
P20D6
Exhaust Aftertreatment Fuel Injector B Stuck Closed
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Generic OBD-II
P20D7
Exhaust Aftertreatment Fuel Supply Control Circuit/Open
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Generic OBD-II
P20D8
Volkswagen CJAA aftertreatment fuel-control deviation
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Generic OBD-II
P20D9
Exhaust Aftertreatment Fuel Supply Control Circuit Low
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Generic OBD-II
P20DA
Exhaust Aftertreatment Fuel Supply Control Circuit High
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Generic OBD-II
P20DB
Exhaust Aftertreatment Fuel Supply Control Stuck Open
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Generic OBD-II
P20DC
Exhaust Aftertreatment Fuel Supply Control Stuck Closed
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Generic OBD-II
P20DD
Exhaust Aftertreatment Fuel Pressure Sensor Circuit
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Generic OBD-II
P20DE
Exhaust Aftertreatment Fuel Pressure Sensor Circuit Range/Performance
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Generic OBD-II
P20DF
Exhaust Aftertreatment Fuel Pressure Sensor Circuit Low
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Generic OBD-II
P20E0
Exhaust Aftertreatment Fuel Pressure Sensor Circuit High
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Generic OBD-II
P20E1
Exhaust Aftertreatment Fuel Pressure Sensor Circuit Intermittent/Erratic
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Generic OBD-II
P20E2
exhaust temperature sensors are compared after a long soak
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Generic OBD-II
P20E3
Exhaust Gas Temperature Sensor 1/3 Correlation Bank 1
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Generic OBD-II
P20E4
particulate-filter temperature correlation uses startup references
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Generic OBD-II
P20E5
Exhaust Gas Temperature Sensor 1/2 Correlation Bank 2
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Generic OBD-II
P20E6
Reductant Injection Air Pressure Too Low
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Generic OBD-II
P20E7
Reductant Injection Air Pressure Too High
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Generic OBD-II
P20E8
When DEF pressure fails to follow the commanded setpoint
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Generic OBD-II
P20E9
reductant pressure exceeds its current target
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Generic OBD-II
P20EA
Reductant Control Module Power Relay De-Energized Performance - Too Early
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Generic OBD-II
P20EB
Reductant Control Module Power Relay De-Energized Performance - Too Late
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Generic OBD-II
P20EC
SCR NOx Catalyst - Over Temperature Bank 1
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Generic OBD-II
P20ED
SCR NOx Pre-Catalyst - Over Temperature Bank 1
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Generic OBD-II
P20EE
SCR efficiency is a filtered model-based judgment
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Generic OBD-II
P20EF
SCR NOx Pre- Catalyst Efficiency Below Threshold Bank 1
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Generic OBD-II
P20F0
SCR NOx Catalyst - Over Temperature Bank 2
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Generic OBD-II
P20F1
SCR NOx Pre-Catalyst - Over Temperature Bank 2
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Generic OBD-II
P20F2
SCR NOx Catalyst Efficiency Below Threshold Bank 2
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Generic OBD-II
P20F3
SCR NOx Pre- Catalyst Efficiency Below Threshold Bank 2
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Generic OBD-II
P20F4
Reductant Consumption Too Low
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Generic OBD-II
P20F5
Reductant Consumption Too High
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Generic OBD-II
P20F6
Reductant Injection Valve Stuck Open Bank 1 Unit 1
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Generic OBD-II
P20F7
Reductant Injection Valve Stuck Open Bank 2 Unit 1
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Generic OBD-II
P20F8
swirl-flap position does not track a settled command
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Generic OBD-II
P20F9
Intake Manifold Runner Control Circuit Performance Bank 2
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Generic OBD-II
P20FA
Reductant Pump B Control Circuit/Open
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Generic OBD-II
P20FB
Reductant Pump B Control Performance/Stuck Off
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Generic OBD-II
P20FC
Reductant Pump B Control Circuit Low
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Generic OBD-II
P20FD
Reductant Pump B Control Circuit High
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Generic OBD-II
P20FE
first DEF injector needs excessive delivery compensation
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Generic OBD-II
P20FF
reductant-controller performance includes memory and calibration checks
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Generic OBD-II
P2100
Why a throttle motor circuit-open code can include driver overheating
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Generic OBD-II
P2101
Throttle position differs from its modeled response
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Generic OBD-II
P2102
throttle motor driver reports a short-to-ground condition
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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.