Oxygen Sensor Diagnostic Codes
Oxygen sensors are critical for fuel efficiency and emissions. Here's how to diagnose and fix O2 sensor problems.
Oxygen Sensor Circuit Malfunction Bank 1 Sensor 1
The upstream oxygen sensor on bank 1 is not functioning properly. This sensor is critical for fuel mixture control.
Oxygen Sensor Circuit Low Voltage Bank 1 Sensor 1
The upstream oxygen sensor on bank 1 is reading consistently low voltage, indicating a lean condition or sensor failure.
Oxygen Sensor Circuit High Voltage Bank 1 Sensor 1
The upstream oxygen sensor on bank 1 is reading consistently high voltage, indicating a rich condition or sensor failure.
Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1
The upstream oxygen sensor on bank 1 is responding too slowly to changes in exhaust oxygen content.
Oxygen Sensor Circuit No Activity Detected Bank 1 Sensor 1
The upstream oxygen sensor on bank 1 shows no activity or switching between rich and lean conditions.
Oxygen Sensor Heater Circuit Malfunction Bank 1 Sensor 1
The heater circuit for the upstream oxygen sensor on bank 1 is not working properly.
Oxygen Sensor Circuit Malfunction Bank 1 Sensor 2
The downstream oxygen sensor on bank 1 (after catalytic converter) is not functioning properly.
Oxygen Sensor Circuit Low Voltage Bank 1 Sensor 2
The downstream oxygen sensor on bank 1 is reading consistently low voltage.
Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2
The downstream oxygen sensor on bank 1 is reading consistently high voltage.
Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2
The downstream oxygen sensor on bank 1 is responding too slowly to exhaust changes.
Oxygen Sensor Circuit No Activity Bank 1 Sensor 2
The downstream oxygen sensor on bank 1 shows no switching activity.
Oxygen Sensor Heater Circuit Malfunction Bank 1 Sensor 2
The heater circuit for the downstream oxygen sensor on bank 1 is not working.
P0142: Fuel Pressure Regulator Circuit Malfunction
The fuel pressure regulator circuit is malfunctioning, causing the fuel pressure to be outside the normal operating range.
P0143: Fuel Pressure Regulator Circuit Malfunction
The fuel pressure regulator circuit is malfunctioning, causing the fuel pressure to be outside the normal operating range.
P0144: Fuel Pressure Regulator Circuit Malfunction
The fuel pressure regulator circuit has malfunctioned, causing the fuel pressure to be outside the normal operating range.
P0145: Fuel Pressure Regulator Circuit Malfunction
The fuel pressure regulator circuit has malfunctioned, causing the fuel pressure to be outside the normal operating range.
P0146: Fuel Pressure Regulator Circuit Low Input
The fuel pressure regulator circuit is not receiving the correct input signal, which can cause issues with fuel delivery and engine performance.
P0147: Fuel Pressure Regulator Circuit Low Input
The fuel pressure regulator circuit is not receiving the correct input signal, which can cause issues with fuel delivery and engine performance.
P0148: Fuel Pressure Regulator Circuit Malfunction
The fuel pressure regulator circuit is malfunctioning, causing the fuel pressure to be out of range. This can lead to poor engine performance, rough idling, and decreased fuel efficiency.
P0149: Fuel Heater Circuit Malfunction
The fuel heater circuit has malfunctioned, preventing the fuel from heating up properly, which can cause issues with fuel delivery and engine performance.
Oxygen Sensor Circuit Malfunction Bank 2 Sensor 1
The upstream oxygen sensor on bank 2 is not functioning properly. This applies to V6/V8 engines.
Oxygen Sensor Circuit Low Voltage Bank 2 Sensor 1
The upstream oxygen sensor on bank 2 is reading consistently low voltage.
Oxygen Sensor Circuit High Voltage Bank 2 Sensor 1
The upstream oxygen sensor on bank 2 is reading consistently high voltage.
Oxygen Sensor Circuit Slow Response Bank 2 Sensor 1
The upstream oxygen sensor on bank 2 is responding too slowly to exhaust changes.
Oxygen Sensor Circuit No Activity Bank 2 Sensor 1
The upstream oxygen sensor on bank 2 shows no switching activity.
Oxygen Sensor Heater Circuit Malfunction Bank 2 Sensor 1
The heater circuit for the upstream oxygen sensor on bank 2 is not working.
P0156: Fuel Trim Malfunction Bank 2 Sensor 2
The fuel trim system has detected a malfunction in the fuel delivery system, specifically with the secondary air/fuel mixture sensor on bank 2.
P0157: Fuel Heated Oxygen Sensor (Bank 2 Sensor 2) Circuit Low Voltage
The fuel heated oxygen sensor (FHOS) on bank 2 sensor 2 is not providing a sufficient voltage signal to the engine control module (ECM). This can be caused by a faulty sensor, wiring issue, or a problem with the sensor's heating element.
P0158: Fuel Trim Malfunction (Bank 2 Sensor 2)
The fuel trim system has detected a malfunction in the fuel delivery and air intake system on bank 2, sensor 2. This can cause the engine to run rich or lean, leading to decreased performance and fuel efficiency.
P0159: Fuel Trim Malfunction Bank 2 Sensor 2
The fuel trim system has detected a malfunction in the fuel delivery system, specifically in Bank 2 Sensor 2, which may be causing the engine to run rich or lean.