Engine-Codes - Chevrolet - P0161 CHEVROLET

P0161 CHEVROLET - HO2S Heater Performance Bank 2 Sensor 2

Repair Importance Level: 2/3
Repair Difficulty Level: 2/3  What is this?
Table of contents

P0161 CHEVROLET 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 is the P0161 CHEVROLET code repair?

Start by checking 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

What is the cost to diagnose the P0161 CHEVROLET code

Labor: 1.0

The cost to diagnose the P0161 CHEVROLET code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
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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 CHEVROLET Meaning

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.

More Information

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