HO2S Heater Performance Bank 2 Sensor 2
Table of contents
- Possible Causes
- How To Fix
- Tech Notes
- Cost To Diagnose
- When is the code detected
- Possible Symptoms
- Description
P0161 Possible Causes
- Faulty Rear Heated Oxygen Sensor Bank 2
- Rear Heated Oxygen Sensor Bank 2 harness is open or shorted
- Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection
- Inappropriate fuel pressure
- Faulty fuel injectors
- Intake air leaks
- Exhaust gas leaks
How do I fix code P0161?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- Replacing the Rear Heated Oxygen Sensor Bank 2 usually takes care of the problem
Cost of diagnosing the P0161 code
The cost of diagnosing the P0161 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
When is the code detected
The Powertrain Control Module (PCM) runs the heater test only on a cold start (depends on the cumulative air flow) and only once an ignition cycle. When you start the engine the PCM monitors the HO2S voltage. When the HO2S voltage goes above or below the bias range threshold, the PCM determines how much time it took. If the PCM detects that the process took too much time for the HO2S to enter into normal operating range, the P0161 code will set. The time the process takes the HO2S to reach operating temperature is based on the amount of air that flows into the engine.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Possible higher than usual fuel consumption
P0161 Description
The Powertrain Control Module (PCM) supplies a bias voltage (approximately 450 mV) on the Heated Oxygen Sensor (HO2S) signal high and low circuits. When you turn the ignition to the ON position, battery voltage is supplied to the HO2S heater. As the heater reaches the operating temperature, the HO2S voltage responds by changing from a bias voltage range to the normal operation. Typically, as the HO2S reaches the operating temperature, the HO2S voltage goes from a bias voltage to a voltage below 300 mV. Depending on the exhaust gas content, it is possible for the HO2S voltage to go above 450 mV.