OBDII Codes

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Common OBDII Codes

When an O2 sensor failure occurs, a DTC or diagnostic trouble code is recorded in the ECU and a check engine light appears on the vehicle’s dash. The DTC must be retrieved using a scanning tool. There are generic or standard OBDII codes along with enhanced or OEM specific codes. Below is a list of the more common OBDII codes, along with the possible cause or causes of the code.

Code Description Location Possible Causes
P0030 HO2S Heater Control Circuit Bank 1 Sensor 1 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0031 HO2S Heater Control Circuit Low Bank 1 Sensor 1 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0032 HO2S Heater Control Circuit High Bank 1 Sensor 1 Faulty ECM. Sensor heater broken or circuit open. Replacement sensor installed with incorrect heater current values.
P0036 HO2S Heater Control Circuit Bank 1 Sensor 2 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0037 HO2S Heater Control Circuit Low Bank 1 Sensor 2 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0038 HO2S Heater Control Circuit High Bank 1 Sensor 2 Faulty ECM. Sensor heater broken or circuit open. Replacement sensor installed with incorrect heater current values.
P0040 Upstream O2’s Swapped From Bank to Bank Sensors connected incorrectly.
P0041 Downstream O2’s Swapped From Bank to Bank Sensors connected incorrectly.
P0042 HO2S Heater Control Circuit Bank 1 Sensor 3 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0043 HO2S Heater Control Circuit Low Bank 1 Sensor 3 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0044 HO2S Heater Control Circuit High Bank 1 Sensor 3 Faulty ECM. Sensor heater broken or circuit open. Replacement sensor installed with incorrect heater current values.
P0050 HO2S Heater Control Circuit Bank 2 Sensor 1 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0051 HO2S Heater Control Circuit Low Bank 2 Sensor 1 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0052 HO2S Heater Control Circuit High Bank 2 Sensor 1 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0053 HO2S Heater Resistance Bank 1 Sensor 1 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0054 HO2S Heater Resistance Bank 1 Sensor 2 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0055 HO2S Heater Resistance Bank 1 Sensor 3 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0056 HO2S Heater Control Circuit Bank 2 Sensor 2 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0057 HO2S Heater Control Circuit Low Bank 2 Sensor 2 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0058 HO2S Heater Control Circuit High Bank 2 Sensor 2 Faulty ECM. Sensor heater broken or circuit open. Replacement sensor installed with incorrect heater current values.
P0059 HO2S Heater Resistance Bank 2 Sensor 1 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0060 HO2S Heater Resistance Bank 2 Sensor 1 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0061 HO2S Heater Resistance Bank 2 Sensor 1 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0062 HO2S Heater Control Circuit Bank 2 Sensor 3 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0063 HO2S Heater Control Circuit Low Bank 2 Sensor 3 Faulty ECM. Sensor heater broken or circuit shorted. Replacement sensor installed with incorrect heater current values.
P0064 HO2S Heater Control Circuit High Bank 2 Sensor 3 Faulty ECM. Sensor heater broken or circuit open. Replacement sensor installed with incorrect heater current values.
P0130 O2 Sensor Circuit Malfunction Bank 1 Sensor 1 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0131 O2 Sensor Circuit Low Voltage Bank 1 Sensor 1 Short in wiring between sensor ground and signal wire. Silicone poisoning. Ethylene glycol poisoning. Failed sensor heater. Heater circuit fuse.
P0132 O2 Sensor No Activity Detected Bank 1 Sensor 1 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0130 O2 Sensor Circuit Malfunction Bank 1 Sensor 1 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0130 O2 Sensor Circuit Malfunction Bank 1 Sensor 1 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0131 O2 Sensor Circuit Low Voltage Bank 1 Sensor 1 Short in wiring between sensor ground and signal wire. Silicone poisoning. Ethylene glycol poisoning. Failed sensor heater. Heater circuit fuse.
P0132 O2 Sensor No Activity Detected Bank 1 Sensor 1 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0133 O2 Sensor Circuit Slow Resistance Bank 1 Sensor 1 Sensor electrode protective coated with carbon. Silicone poisoning. Ethylene glycol poisoning. Failed sensor heater. Heater circuit fuse.
P0134 O2 Sensor Circuit No Activity Detected Bank 1 Sensor 1 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0135 O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0136 O2 Sensor Circuit Malfunction Bank 1 Sensor 2 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0137 O2 Sensor Circuit Malfunction Bank 1 Sensor 2 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0138 O2 Sensor Circuit High Voltage Bank 1 Sensor 2 Short in wiring between heater circuit and signal wire. Sensor immersed in wter. Silicone or ethylene glycol poisoning of the sensing electrode.
P0139 O2 Sensor Circuit Slow Response Bank 1 Sensor 2 Sensor electrode protective coated with carbon. Silicone poisoning. Ethylene glycol poisoning. Failed sensor heater. Heater circuit fuse.
P0140 O2 Sensor Circuit No Activity Detected Bank 1 Sensor 2 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0141 O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 2 Sensor heater shorted or open. Replacement sensor installed with incorrect heater curent values. Open or shorted electrical connections. Heater circuit fuse.
P0142 O2 Sensor Circuit Malfunction Bank 1 Sensor 3 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0143 O2 Circuit Low Voltage Bank 1 Sensor 3 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0144 O2 Sensor Circuit High Voltage Bank 1 Sensor 3 Short in wiring between heater circuit and signal wire. Sensor immersed in water. Silicone or ethylene glycol poisoning of the sensing electrode.
P0145 O2 Sensor Circuit Slow Repsonse Bank 1 Sensor 3 Sensor electrode protective coated with carbon. Silicone poisoning. Ethylene glycol poisoning. Failed sensor heater. Heater circuit fuse.
P0146 O2 Sensor Circuit No Activity Detected Bank 1 Sensor 3 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0147 O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 3 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current calues. Open or shorted elctrical connections. Heater circiut fuse.
P0150 O2 Sensor Circuit Malfunction Bank 2 Sensor 1 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0151 O2 Sensor Circuit Low Voltage Bank 2 Sensor 1 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0152 O2 Sensor Circuit High Voltage Bank 2 Sensor 1 Short in wiring between heater circuit and signal wire. Sensor immersed in water. Silicone or ethylene glycol poisoning of the sensing electrode.
P0153 O2 Sensor Circuit Slow Response Bank 2 Sensor 1 Sensor electrode protective coated with carbon. Silicone poisoning. Ethylene glycol poisoning. Failed sensor heater. Heater circuit fuse.
P0154 O2 Sensor Circuit No Activity Detected Bank 2 Sensor 1 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0155 O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0156 O2 Sensor Circuit Sensor Malfunction Bank 2 Sensor 2 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0157 O2 Sensor Circuit Low Voltage Bank 2 Sensor 2 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0158 O2 Sensor Circuit High Voltage Bank 2 Sensor 2 Short in wiring between heater circuit and signal wire. Sensor immersed in water. Silicone or ethylene glycol poisoning of the sensing electrode.
P0159 O2 Sensor Circuit Slow Response Bank 2 Sensor 2 Sensor electrode protective coated with carbon. Silicone poisoning. Ethylene glycol poisoning. Failed sensor heater. Heater circuit fuse.
P0160 O2 Sensor Circuit No Activity Detected Bank 2 Sensor 2 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0161 O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 2 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0162 O2 Sensor Circuit Malfunction Bank 2 Sensor 3 Broken sensor element. Sensor disconnected. Shorted wiring. Catastrophic failure of sensor due to thermal shock.
P0163 O2 Sensor Circuit Low Voltage Bank 2 Sensor 3 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0164 O2 Sensor Circuit High Voltage Bank 2 Sensor 3 Short in wiring between heater circuit and signal wire. Sensor immersed in water. Silicone or ethylene glycol poisoning of the sensing electrode.
P0165 O2 Sensor Circuit Slow Response Bank 2 Sensor 3 Sensor electrode protective coated with carbon. Silicone poisoning. Ethylene glycol poisoning. Failed sensor heater. Heater circuit fuse.
P0166 O2 Sensor Circuit No Activity Detected Bank 2 Sensor 3 Short in wiring between sensor ground and signal wire. Silicone or ethylene glycol poisoning of the air reference electrode.
P0167 O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 3 Sensor heater shorted or open. Replacement sensor installed with incorrect heater current values. Open or shorted electrical connections. Heater circuit fuse.
P0170 Fuel Trim Malfunction Bank 1 Vacuum Leak. Gas in engine oil. Air leaks. Bad O2 Sensor.
P0171 System Too Lean Bank 1 Leaking exhuast gasket or vauum lines. Defective fuel injector(s). DAmaged fuel pump. Clogged fule filter.
P0172 System Too Rich Bank 1 Vacuum leak. Fuel pressure or delivery problem. Faulty MAF sensor.
P0173 Fuel Trim Malfunction Bank 2 Vacuum Leak. Gas in engine oil. Air leaks. Bad O2 Sensor.
P0174 System Too Lean Bank 2 Leaking exhuast gasket or vauum lines. Defective fuel injector(s). DAmaged fuel pump. Clogged fule filter.
P0175 System Too Rich Bank 2 Vacuum Leak. Gas in engine oil. Air leaks. Bad O2 Sensor.
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