Air & Fuel Mixture ControlOBD2 Codes

P0158 – Meaning, Causes, Symptoms, & Fixes

Code P0158 Definition

O2 Sensor Circuit High Voltage (Bank 2, Sensor 2)

What Does P0158 Mean?

Oxygen sensor 2 is the downstream oxygen sensor in relationship to the catalytic converter. It measures the amount of air and fuel coming out of the catalytic converter to ensure the catalytic converter is functioning properly. If the voltage is high (approx. .9V) there is an excess of fuel in the mixture. If the voltage is low (approx. .1V) then there is an excess of air in the mixture. Therefore, the downstream oxygen sensor (sensor 2) should produce a steady voltage of approximately 0.45 volts. When trouble code P0158 is set, this indicates that there is a high voltage (steadily above .9 volts) for more than 10 seconds indicating a lack of oxygen in the exhaust stream and an abundance of fuel at sensor 2 on bank 2 of the engine.

What Are the Symptoms of Code P0158?

  • Check Engine Light
  • Engine runs rich
  • Lower fuel economy
  • Rough idle
  • Strong fumes

What Is the Cause of Code P0158?

  • Faulty O2 Sensor
  • Short to battery voltage in O2 sensor signal circuit
  • Corroded wiring
  • Fuel pressure too high
  • Engine coolant temperature sensor

How Serious Is Code P0158? – Moderate

It is okay to drive a vehicle with P0158 for a short period of time, but driving with this code for an extended period of time can damage the catalytic converter(s).

Code P0158 Common Diagnosis Mistakes

Replacing the O2 sensor without checking to see if the vehicle is running rich due to another problem.

Tools Needed to Diagnose Code P0158:

How to Diagnose and Repair Code P0158:

Difficulty of Diagnosis and Repair – (2 out of 5)

  1. Check the wire at O2 sensor for damage; if damaged, repair or replace affected harness.
  2. Check voltage at the O2 sensor; if the voltage is steadily high (.9V or higher) the O2 sensor may be faulty. Before replacing, check the following:
    1. Verify coolant temperature is reading properly (consult vehicle manual for specification)
    2. Verify fuel pressure is within spec.
  3. If the O2 sensor is reading high voltage and the fuel pressure and coolant temperature are within spec, replace the bank 2 downstream O2 sensor.

Estimated Cost of Repair

For error code P0158, one or more of the below repairs may be needed to solve the underlying issue. For each possible repair, the estimated cost of repair includes the cost of the relevant parts and the cost of labor required to make the repair.

  • Oxygen sensor $200-$300
  • Fuel pressure regulator $200-$400
  • Engine coolant temperature sensor $150-$200

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  1. Thank you!!!

    1. Didn’t tell me the location of the 02 senser that would be helpful

  2. Oxygen sensor 2 is the downstream oxygen sensor in relationship to the catalytic converter. Its after the catalytic converter in the exhaust pipe

  3. “Bank 2, Sensor 2”
    Bank 2 is the exhaust coming from cylinder #2 (4,6,8,etc).
    Bank 1 is the exhaust coming from cylinder #1 (3,5,7,etc)
    You’ll need to look up your vehicle’s firing order to tell which is which.

    On a V engine these will be different sides. Some inline engines have separate bank 1 and bank 2 exhausts or if there is just one exhaust pipe and sensor for both they are referred to as bank 1.

    Sensor 2 means downstream after the catalytic converter.

  4. I had a po158 code on my 02 Jeep Liberty I cleared the code a couple of times and got a number 6 engine miss Fire I had Also just changed a heater core I changed the number 6 coil and there was water in the hole from changing the heater coil I cleaned the water out replaced the coil and code and the Jeep runs fine I didn’t have to change the 02 sensor it’s best to look at everything before spending money you don’t have to I saved the old coil because it was wet to but sense it was old I decided to change it

  5. O2 sensor is 30 bucks from AutoZone, what are you talking about?

    1. The cost for an O2 sensor replacement depends on a variety of factors, including the make/model of your vehicle, the quality of the parts, and how many are needed. Learn more here:

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