Emissions Codes
704 OBD-II diagnostic trouble codes in this category.
Showing page 1 of 8 (704 codes total)
| Code | Description | Subsystem | Severity |
|---|---|---|---|
| P0030 | HO2S Heater Control Circuit (Bank 1 Sensor 1) | Oxygen Sensor | Medium |
| P0031 | HO2S Heater Control Circuit Low (Bank 1 Sensor 1) | Oxygen Sensor | Medium |
| P0032 | HO2S Heater Control Circuit High (Bank 1 Sensor 1) | Oxygen Sensor | Medium |
| P0036 | HO2S Heater Control Circuit (Bank 1 Sensor 2) | Oxygen Sensor | Medium |
| P0037 | HO2S Heater Control Circuit Low (Bank 1 Sensor 2) | Oxygen Sensor | Medium |
| P0038 | HO2S Heater Control Circuit High (Bank 1 Sensor 2) | Oxygen Sensor | Medium |
| P0040 | O2 Sensor Signals Swapped Bank 1 Sensor 1/Bank 2 Sensor 1 | Oxygen Sensor | Medium |
| P0041 | O2 Sensor Signals Swapped Bank 1 Sensor 2/Bank 2 Sensor 2 | Oxygen Sensor | Medium |
| P0042 | HO2S Heater Control Circuit Bank 1 Sensor 3 | Oxygen Sensor | Medium |
| P0043 | HO2S Heater Control Circuit Low Bank 1 Sensor 3 | Oxygen Sensor | Medium |
| P0044 | HO2S Heater Control Circuit High Bank 1 Sensor 3 | Oxygen Sensor | Medium |
| P0050 | HO2S Heater Control Circuit (Bank 2 Sensor 1) | Oxygen Sensor | Medium |
| P0051 | HO2S Heater Control Circuit Low (Bank 2 Sensor 1) | Oxygen Sensor | Medium |
| P0052 | HO2S Heater Control Circuit High (Bank 2 Sensor 1) | Oxygen Sensor | Medium |
| P0053 | HO2S Heater Resistance Bank 1 Sensor 1 | Oxygen Sensor | Low |
| P0054 | HO2S Heater Resistance Bank 1 Sensor 2 | Oxygen Sensor | Low |
| P0055 | HO2S Heater Resistance Bank 1 Sensor 3 | Oxygen Sensor | Low |
| P0056 | HO2S Heater Control Circuit (Bank 2 Sensor 2) | Oxygen Sensor | Medium |
| P0057 | HO2S Heater Control Circuit Low (Bank 2 Sensor 2) | Oxygen Sensor | Medium |
| P0058 | HO2S Heater Control Circuit High (Bank 2 Sensor 2) | Oxygen Sensor | Medium |
| P0059 | HO2S Heater Resistance Bank 2 Sensor 1 | Oxygen Sensor | Low |
| P0060 | HO2S Heater Resistance Bank 2 Sensor 2 | Oxygen Sensor | Low |
| P0061 | HO2S Heater Resistance Bank 2 Sensor 3 | Oxygen Sensor | Low |
| P0062 | HO2S Heater Control Circuit Bank 2 Sensor 3 | Oxygen Sensor | Medium |
| P0063 | HO2S Heater Control Circuit Low Bank 2 Sensor 3 | Oxygen Sensor | Medium |
| P0064 | HO2S Heater Control Circuit High Bank 2 Sensor 3 | Oxygen Sensor | Medium |
| P00D1 | HO2S Heater Control Circuit Range/Performance Bank 1 Sensor 1 | Oxygen Sensor | Medium |
| P00D2 | HO2S Heater Control Circuit Range/Performance Bank 1 Sensor 2 | Oxygen Sensor | Medium |
| P00D3 | HO2S Heater Control Circuit Range/Performance Bank 2 Sensor 1 | Oxygen Sensor | Medium |
| P00D4 | HO2S Heater Control Circuit Range/Performance Bank 2 Sensor 2 | Oxygen Sensor | Medium |
| P00D5 | HO2S Sensor Correlation Bank 1 Sensor 1/Bank 1 Sensor 2 | Oxygen Sensor | Medium |
| P00D6 | HO2S Sensor Correlation Bank 2 Sensor 1/Bank 2 Sensor 2 | Oxygen Sensor | Medium |
| P0130 | O2 Sensor Circuit Malfunction (Bank 1 Sensor 1) | Oxygen Sensor | Medium |
| P0131 | O2 Sensor Circuit Low Voltage (Bank 1 Sensor 1) | Oxygen Sensor | Medium |
| P0132 | O2 Sensor Circuit High Voltage (Bank 1 Sensor 1) | Oxygen Sensor | Medium |
| P0133 | O2 Sensor Circuit Slow Response (Bank 1 Sensor 1) | Oxygen Sensor | Medium |
| P0134 | O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1) | Oxygen Sensor | Medium |
| P0135 | O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1) | Oxygen Sensor | Medium |
| P0136 | O2 Sensor Circuit Malfunction (Bank 1 Sensor 2) | Oxygen Sensor | Medium |
| P0137 | O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2) | Oxygen Sensor | Medium |
| P0138 | O2 Sensor Circuit High Voltage (Bank 1 Sensor 2) | Oxygen Sensor | Medium |
| P0139 | O2 Sensor Circuit Slow Response (Bank 1 Sensor 2) | Oxygen Sensor | Medium |
| P013A | O2 Sensor Slow Response - Rich to Lean Bank 1 Sensor 2 | Oxygen Sensor | Medium |
| P013B | O2 Sensor Slow Response - Lean to Rich Bank 1 Sensor 2 | Oxygen Sensor | Medium |
| P013C | O2 Sensor Slow Response - Rich to Lean Bank 2 Sensor 2 | Oxygen Sensor | Medium |
| P013D | O2 Sensor Slow Response - Lean to Rich Bank 2 Sensor 2 | Oxygen Sensor | Medium |
| P013E | O2 Sensor Delayed Response - Rich to Lean Bank 1 Sensor 2 | Oxygen Sensor | Medium |
| P013F | O2 Sensor Delayed Response - Lean to Rich Bank 1 Sensor 2 | Oxygen Sensor | Medium |
| P0140 | O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2) | Oxygen Sensor | Medium |
| P0141 | O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2) | Oxygen Sensor | Medium |
| P0142 | O2 Sensor Circuit Bank 1 Sensor 3 | Oxygen Sensor | Medium |
| P0143 | O2 Sensor Circuit Low Voltage Bank 1 Sensor 3 | Oxygen Sensor | Medium |
| P0144 | O2 Sensor Circuit High Voltage Bank 1 Sensor 3 | Oxygen Sensor | Medium |
| P0145 | O2 Sensor Circuit Slow Response Bank 1 Sensor 3 | Oxygen Sensor | Low |
| P0146 | O2 Sensor Circuit No Activity Detected Bank 1 Sensor 3 | Oxygen Sensor | Medium |
| P0147 | O2 Sensor Heater Circuit Bank 1 Sensor 3 | Oxygen Sensor | Low |
| P014A | O2 Sensor Delayed Response - Rich to Lean Bank 2 Sensor 2 | Oxygen Sensor | Medium |
| P014B | O2 Sensor Delayed Response - Lean to Rich Bank 2 Sensor 2 | Oxygen Sensor | Medium |
| P014C | O2 Sensor Slow Response - Rich to Lean Bank 1 Sensor 1 | Oxygen Sensor | Medium |
| P014D | O2 Sensor Slow Response - Lean to Rich Bank 1 Sensor 1 | Oxygen Sensor | Medium |
| P014E | O2 Sensor Slow Response - Rich to Lean Bank 2 Sensor 1 | Oxygen Sensor | Medium |
| P014F | O2 Sensor Slow Response - Lean to Rich Bank 2 Sensor 1 | Oxygen Sensor | Medium |
| P0150 | O2 Sensor Circuit Malfunction (Bank 2 Sensor 1) | Oxygen Sensor | Medium |
| P0151 | O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1) | Oxygen Sensor | Medium |
| P0152 | O2 Sensor Circuit High Voltage (Bank 2 Sensor 1) | Oxygen Sensor | Medium |
| P0153 | O2 Sensor Circuit Slow Response (Bank 2 Sensor 1) | Oxygen Sensor | Medium |
| P0154 | O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 1) | Oxygen Sensor | Medium |
| P0155 | O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1) | Oxygen Sensor | Medium |
| P0156 | O2 Sensor Circuit Malfunction (Bank 2 Sensor 2) | Oxygen Sensor | Medium |
| P0157 | O2 Sensor Circuit Low Voltage (Bank 2 Sensor 2) | Oxygen Sensor | Medium |
| P0158 | O2 Sensor Circuit High Voltage (Bank 2 Sensor 2) | Oxygen Sensor | Medium |
| P0159 | O2 Sensor Circuit Slow Response (Bank 2 Sensor 2) | Oxygen Sensor | Medium |
| P015A | O2 Sensor Delayed Response - Rich to Lean Bank 1 Sensor 1 | Oxygen Sensor | Medium |
| P015B | O2 Sensor Delayed Response - Lean to Rich Bank 1 Sensor 1 | Oxygen Sensor | Medium |
| P015C | O2 Sensor Delayed Response - Rich to Lean Bank 2 Sensor 1 | Oxygen Sensor | Medium |
| P015D | O2 Sensor Delayed Response - Lean to Rich Bank 2 Sensor 1 | Oxygen Sensor | Medium |
| P0160 | O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2) | Oxygen Sensor | Medium |
| P0161 | O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2) | Oxygen Sensor | Medium |
| P0162 | O2 Sensor Circuit Bank 2 Sensor 3 | Oxygen Sensor | Medium |
| P0163 | O2 Sensor Circuit Low Voltage Bank 2 Sensor 3 | Oxygen Sensor | Medium |
| P0164 | O2 Sensor Circuit High Voltage Bank 2 Sensor 3 | Oxygen Sensor | Medium |
| P0165 | O2 Sensor Circuit Slow Response Bank 2 Sensor 3 | Oxygen Sensor | Low |
| P0166 | O2 Sensor Circuit No Activity Detected Bank 2 Sensor 3 | Oxygen Sensor | Medium |
| P0167 | O2 Sensor Heater Circuit Bank 2 Sensor 3 | Oxygen Sensor | Low |
| P019A | O2 Sensor Delayed Response - Rich to Lean Bank 1 Sensor 3 | Oxygen Sensor | Medium |
| P019B | O2 Sensor Delayed Response - Lean to Rich Bank 1 Sensor 3 | Oxygen Sensor | Medium |
| P019C | O2 Sensor Delayed Response - Rich to Lean Bank 2 Sensor 3 | Oxygen Sensor | Medium |
| P019D | O2 Sensor Delayed Response - Lean to Rich Bank 2 Sensor 3 | Oxygen Sensor | Medium |
| P01F1 | O2 Sensor Circuit Bank 1 Sensor 4 | Oxygen Sensor | Medium |
| P01F2 | O2 Sensor Circuit Low Voltage Bank 1 Sensor 4 | Oxygen Sensor | Medium |
| P01F3 | O2 Sensor Circuit High Voltage Bank 1 Sensor 4 | Oxygen Sensor | Medium |
| P01F4 | O2 Sensor Circuit Slow Response Bank 1 Sensor 4 | Oxygen Sensor | Medium |
| P01F5 | O2 Sensor Circuit No Activity Detected Bank 1 Sensor 4 | Oxygen Sensor | Medium |
| P01F6 | O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 4 | Oxygen Sensor | Medium |
| P01F7 | O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 4 | Oxygen Sensor | Medium |
| P02E3 | Diesel Intake Air Flow A Control Circuit High | Emission Control | Medium |
| P02E4 | Diesel Intake Air Flow A Control Stuck Open | Diesel Emissions | High |
| P02E5 | Diesel Intake Air Flow A Control Stuck Closed | Diesel Emissions | High |
| P02E6 | Diesel Intake Air Flow A Position Sensor Circuit | Diesel Emissions | High |
| P02E7 | Diesel Intake Air Flow A Position Sensor Circuit Range/Performance | Diesel Emissions | High |
About Emissions Codes
This page lists all 704 OBD-II diagnostic trouble codes classified under the Emissions category. These codes are stored by your vehicle's onboard computer when a sensor detects a malfunction in the emissions system. Each code begins with a letter indicating the system (P for Powertrain, B for Body, C for Chassis, U for Network) followed by four digits that identify the specific fault.
When your check engine light comes on, an OBD-II scanner reads these stored codes to help pinpoint the problem. Generic codes (where the second digit is 0) follow the SAE J2012 standard and mean the same thing on every vehicle. Manufacturer-specific codes (where the second digit is 1) may have different meanings depending on the vehicle brand.
Click any code in the table above to see its full description, possible causes, common symptoms, and step-by-step repair guidance. Use the search box to quickly find a specific code within this category.