Technical Description of OBD-II Trouble Code
No Activity Detected in O2 Sensor Circuit (Bank 2 Sensor 2)
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to vehicles equipped with OBD-II. Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
This code indicates a problem with the post-catalyst oxygen sensor, which is either not functioning properly or not functioning at all. The catalytic converter is responsible for controlling emissions, and this particular O2 sensor on Bank 2, position 2 monitors the efficiency of the catalytic converter on that bank.
The Powertrain Control Module (PCM) compares the post-cat O2 sensor to the pre-cat O2 sensors to measure the efficiency of the catalytic converter. The O2 sensor is a four-wire sensor that receives a reference voltage of about half a volt from the PCM and also has a sensor ground. The heater element in the sensor is supplied with 12 volts and a ground to help the sensor warm up faster, allowing the engine to reach closed loop sooner.
The sensor adjusts the reference voltage based on the oxygen content of the exhaust. Changes in oxygen content cause resistance changes in the sensor, which affect the 0.5 volt reference voltage. Oxygen sensors can vary the supplied voltage between 0.1 volts and 0.9 volts. A lean exhaust produces low voltage, causing the supplied 0.5 volts to drop. A rich exhaust produces high voltage, causing the supplied 0.5 volts to increase. Pre-catalyst (front) O2 sensors switch between low and high voltage rapidly, one or two times per second.
However, this sensor is a post-cat O2 sensor and may switch much slower and not vary as much, which is normal. If the sensor “sticks” or there are too few switches in a given time period, the P0160 code may be set.
Symptoms
Symptoms of a P0160 DTC may include:
Causes
Potential causes of a P0160 code include:
Possible Solutions
It is always recommended to visually inspect the exhaust system first. Look for holes near the O2 sensors or wiring harnesses coming into contact with exhaust components. Repair as necessary.
1. Start the engine and allow it to reach operating temperature. Using a scan tool, observe the Bank 2 position 2 O2 sensor. If it is not moving at all, it does not necessarily mean that there is a problem. Post-cat O2 sensors often switch very little. Increase the engine RPM to a fast idle and then recheck the sensor voltage reading. If it starts switching now, the sensor may be sluggish or intermittently going “dormant”. It would be a good idea to replace the sensor at this point. Visually check the O2 sensor for contaminants. If you suspect it is contaminated with coolant or oil, replace it. However, if it still does not respond after increasing the engine RPM, turn off the engine and unplug the 2/2 O2 sensor. With the key on and the engine off, check for 12 volts battery voltage and a good ground to the O2 sensor heater element. If the heater element has no battery voltage, it can cause the O2 sensor to be sluggish and not switch properly, resulting in a P0160 code.
Therefore, diagnose that problem first (there will usually be other codes present). If there is power and ground to the heater element, check that the sensor ground is present. If it is, connect a jumper wire between the sensor ground and signal wire. Now, the 2/2 O2 sensor reading should be low. If so, replace the Bank 2 position 2 O2 sensor. If, after connecting the jumper wire, the O2 sensor reading still remains “stuck”, check for wiring problems, harnesses contacting exhaust components, or broken connectors. Repair as necessary. Then recheck. If no wiring problems can be found and the O2 sensor reading on the scan tool does not change after installing the jumper wire, recheck at the PCM connector. It may be necessary to clip the signal wire near the PCM in a location that will be easy to repair. If it now shows a low voltage reading, then there is a wiring problem. At this point, clipping the offending wire out of the harness and running a new one may be the best solution. However, if it still shows no change, the PCM may be at fault.
