MANUFACTURER REFERENCE
Generic OBD-II code references — Page 54.
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Generic OBD-II
P23A1
O2 Sensor Exhaust Sample Error Bank 2 Sensor 2
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Generic OBD-II
P23A2
Exhaust Heat Exchanger Exhaust Bypass Valve B Control Circuit/Open
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Generic OBD-II
P23A3
Exhaust Heat Exchanger Exhaust Bypass Valve B Control Circuit Low
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Generic OBD-II
P23A4
Exhaust Heat Exchanger Exhaust Bypass Valve B Control Circuit High
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Generic OBD-II
P23A5
Exhaust Heat Exchanger Exhaust Bypass Valve B Control Performance
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Generic OBD-II
P23A6
Exhaust Heat Exchanger Exhaust Bypass Valve B Stuck Open
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Generic OBD-II
P23A7
Exhaust Heat Exchanger Exhaust Bypass Valve B Stuck Closed
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Generic OBD-II
P23A8
Exhaust Heat Exchanger Exhaust Bypass Valve B Position Sensor Stop Performance
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Generic OBD-II
P23A9
Communication Fault – Forced Engine Shutdown
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Generic OBD-II
P23AA
How pressure pulsations expose a stuck turbo bypass valve
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Generic OBD-II
P23AB
NOx Sensor Processor Performance Bank 1 Sensor 3
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Generic OBD-II
P23AC
NOx Sensor Circuit Bank 1 Sensor 3
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Generic OBD-II
P23AD
NOx sensor 3 internal current control is unstable
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Generic OBD-II
P23AE
NOx sensor 3 reports below the lower concentration limit
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Generic OBD-II
P23AF
NOx sensor 3 exceeds the upper concentration range
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Generic OBD-II
P23B0
NOx Sensor Circuit Intermittent Bank 1 Sensor 3
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Generic OBD-II
P23B1
open heater-control circuit at NOx sensor 3
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Generic OBD-II
P23B2
NOx sensor 3 heater control is shorted low
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Generic OBD-II
P23B3
NOx sensor 3 heater control is shorted high
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Generic OBD-II
P23B4
NOx sensor 3 heater-resistance sensing circuit is open
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Generic OBD-II
P23B5
NOx sensor 3 heater resistance misses its target
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Generic OBD-II
P23B6
NOx sensor 3 supply voltage is below range
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Generic OBD-II
P23B7
NOx Sensor Heater Control Circuit Range/Performance Bank 1 Sensor 3
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Generic OBD-II
P23B8
NOx sensor 3 heater-sense path shorted to ground
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Generic OBD-II
P23B9
NOx sensor 3 heater-sense path shorted to power
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Generic OBD-II
P23BA
NOx Sensor Heater Sense Circuit Intermittent Bank 1 Sensor 3
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Generic OBD-II
P23BB
NOx Sensor Heater Resistance Bank 1 Sensor 3
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Generic OBD-II
P23BC
NOx Sensor Calibration Memory Bank 1 Sensor 3
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Generic OBD-II
P23BD
NOx Sensor Performance - Signal Biased/Stuck High Bank 1 Sensor 3
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Generic OBD-II
P23BE
NOx Sensor Performance - Signal Biased/Stuck Low Bank 1 Sensor 3
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Generic OBD-II
P23BF
NOx Sensor Performance - Slow Response Low to High Bank 1 Sensor 3
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Generic OBD-II
P23C0
NOx Sensor Performance - Slow Response High to Low Bank 1 Sensor 3
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Generic OBD-II
P23C1
NOx sensor 3 sensing cavities fail an afterrun self-test
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Generic OBD-II
P23C2
NOx Sensor Delayed Response - High to Low Bank 1 Sensor 3
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Generic OBD-II
P23C3
Engine Coolant Bypass Valve C Position Sensor Circuit
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Generic OBD-II
P23C4
coolant bypass valve C digital position signal low
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Generic OBD-II
P23C5
coolant bypass valve C digital position signal high
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Generic OBD-II
P23C6
coolant bypass valve C motor driver overcurrent
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Generic OBD-II
P23C7
Fuel Heater Control Module Power Control Circuit/Open
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Generic OBD-II
P23C8
Fuel Heater Control Module Power Control Circuit Low
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Generic OBD-II
P23C9
Fuel Heater Control Module Power Control Circuit High
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Generic OBD-II
P23CA
Fuel Rail Heater Control Circuit/Open
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Generic OBD-II
P23CB
Fuel Rail Heater Control Circuit Low
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Generic OBD-II
P23CC
Fuel Rail Heater Control Circuit High
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Generic OBD-II
P23CD
Fuel Heater Control Module Feedback Signal/Open
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Generic OBD-II
P23CE
Fuel Heater Control Module Feedback Signal Performance
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Generic OBD-II
P23CF
Fuel Heater Control Module Feedback Signal Circuit Low
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Generic OBD-II
P23D0
Fuel Heater Control Module Feedback Signal Circuit High
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Generic OBD-II
P23D1
Cylinder 1 Fuel Heater Control Circuit/Open
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Generic OBD-II
P23D2
Cylinder 1 Fuel Heater Control Circuit High
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Generic OBD-II
P23D3
Cylinder 1 Fuel Heater Control Circuit Low
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Generic OBD-II
P23D4
Cylinder 1 Fuel Heater Performance
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Generic OBD-II
P23D5
Cylinder 2 Fuel Heater Control Circuit/Open
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Generic OBD-II
P23D6
Cylinder 2 Fuel Heater Control Circuit High
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Generic OBD-II
P23D7
Cylinder 2 Fuel Heater Control Circuit Low
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Generic OBD-II
P23D8
Cylinder 2 Fuel Heater Performance
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Generic OBD-II
P23D9
Cylinder 3 Fuel Heater Control Circuit/Open
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Generic OBD-II
P23DA
Cylinder 3 Fuel Heater Control Circuit High
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Generic OBD-II
P23DB
Cylinder 3 Fuel Heater Control Circuit Low
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Generic OBD-II
P23DC
Cylinder 3 Fuel Heater Performance
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Generic OBD-II
P23DD
Cylinder 4 Fuel Heater Control Circuit/Open
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Generic OBD-II
P23DE
Cylinder 4 Fuel Heater Control Circuit High
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Generic OBD-II
P23DF
Cylinder 4 Fuel Heater Control Circuit Low
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Generic OBD-II
P23E0
Cylinder 4 Fuel Heater Performance
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Generic OBD-II
P23E1
EGR C Control Circuit/Open
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Generic OBD-II
P23E2
EGR C Control Circuit Performance
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Generic OBD-II
P23E3
EGR C Control Circuit Low
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Generic OBD-II
P23E4
EGR C Control Circuit High
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Generic OBD-II
P23E5
EGR C Control Stuck Open
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Generic OBD-II
P23E6
EGR C Control Stuck Closed
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Generic OBD-II
P23E7
EGR C Flow Insufficient Detected
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Generic OBD-II
P23E8
EGR C Flow Excessive Detected
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Generic OBD-II
P23E9
Camshaft A Position Signal Output Circuit/Open Bank 2
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Generic OBD-II
P23EA
Camshaft A Position Signal Output Circuit Low Bank 2
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Generic OBD-II
P23EB
Camshaft A Position Signal Output Circuit High Bank 2
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Generic OBD-II
P23EC
Camshaft B Position Signal Output Circuit/Open Bank 1
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Generic OBD-II
P23ED
Camshaft B Position Signal Output Circuit Low Bank 1
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Generic OBD-II
P23EE
Camshaft B Position Signal Output Circuit High Bank 1
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Generic OBD-II
P23EF
Camshaft B Position Signal Output Circuit/Open Bank 2
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Generic OBD-II
P23F0
Camshaft B Position Signal Output Circuit Low Bank 2
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Generic OBD-II
P23F1
Camshaft B Position Signal Output Circuit High Bank 2
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Generic OBD-II
P23F2
Cylinder 1 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23F3
Cylinder 2 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23F4
Cylinder 3 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23F5
Cylinder 4 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23F6
Cylinder 5 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23F7
Cylinder 6 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23F8
Cylinder 7 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23F9
Cylinder 8 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23FA
Cylinder 9 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23FB
Cylinder 10 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23FC
Cylinder 11 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23FD
Cylinder 12 Injector B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23FE
Bank 1 System B Air-Fuel Ratio Imbalance
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Generic OBD-II
P23FF
Bank 2 System B Air-Fuel Ratio Imbalance
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Generic OBD-II
P2400
EVAP leak-detection pump control circuit is diagnosed open
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Generic OBD-II
P2401
EVAP leak-detection pump output has a low-circuit fault
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Generic OBD-II
P2402
EVAP pump driver detects unwanted power during its on command
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Generic OBD-II
P2403
low leak-pump sense feedback must persist in Audi's CTUA monitor
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Generic OBD-II
P2404
leak-pump feedback depends on vacuum, power and purge sealing
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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.