P0134 OBD-II Trouble Code: O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0134 code

P0134 is a diagnostic trouble code (DTC) for "O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford$20.00
Toyota$20.00
BMW$20.00
SCHEDULE P0134 DIAGNOSTIC Get a fair and transparent estimate upfront

P0134 code definition

The P0134 diagnostic trouble code is an indication that there is a problem with the oxygen sensor that is positioned before the catalytic converter and on the engine bank that houses cylinder #1.

What the P0134 code means

The oxygen sensor reads the amount of oxygen and fuel that comes through the exhaust to make sure the oxygen to fuel ratio is correct. The oxygen sensor sends that information to the power control module (PCM).

If there is an insufficient amount of oxygen in the exhaust, the power control module (PCM) will decrease the amount of fuel that is being used by the motor. This is important because if there is an insufficient amount of oxygen in the exhaust, the car will use more fuel and emit carbon monoxide into the air.

If there is an insufficient amount of fuel going into the exhaust, the power control module (PCM) will increase the amount of fuel that is being used by the motor. This is important because if there is an insufficient amount of fuel in the exhaust, the car will emit hydrocarbons and nitrogen oxides into the air.

What causes the P0134 code?

A properly working oxygen sensor millivolt reading moves up and down. When the power control module (PCM) detects that the oxygen sensor millivolt at a standstill, and not functioning properly, this will cause the P0134 trouble code. This trouble code can be caused by the following:

  • Faulty heater circuit
  • A wire that is broken or disconnected from the oxygen sensor
  • Corrosion in the connectors
  • Engine vacuum leak
  • A faulty power control module (PCM)

What are the symptoms of the P0134 code?

There are several things that you may experience in correlation with the P0134 trouble code:

  • The Check Engine Light on the dashboard may come on and the engine may stall.

  • You may experience the feeling that your car is running rough or that it is idling poorly.

  • You may also smell something similar to rotten eggs and/or see black smoke billowing from the exhaust.

  • There are times when a driver will not notice any of these symptoms, other than the Check Engine Light being on, but this is a rare occurrence.

How does a mechanic diagnose the P0134 code?

A technician will use an OBD-II scanner to diagnose the P0134 code. The freeze frame data should be captured in order to determine when the code was first set. At this point, the code should be reset and the vehicle test driven.

While test driving, the vehicle needs to reach normal operating temperature in order to see if the code comes back. If the fault code does come back, the wiring that goes to the oxygen sensor and grounds needs to be inspected. While inspecting the technician will look for breaks and corrosion. Live data should be observed in an effort to determine whether the millivolt valves are going low to high.

The oxygen sensor should also be inspected in order to determine whether it has power going to it and that it is receiving the proper signal voltage from the Power Control Module (PCM).

Common mistakes when diagnosing the P0134 code

A mistake that is commonly made when diagnosing the P0134 trouble code is the assumption that the oxygen sensor is the first thing that needs to be replaced without considering other possibilities.

Sometimes the oxygen sensor itself, is not the problem and there are other things that could prevent the oxygen sensor from working, such as the wiring to the oxygen sensor. The wiring should be inspected and ruled out as the cause before replacing the oxygen sensor.

How serious is the P0134 code?

It is not likely that the P0134 trouble code will prevent operation of the vehicle, in that it should start and run, but drivers may experience a lack of power.

Driving with a P0134 trouble code could cause damage to the catalytic converter but it would take an extended period of time to do so. What is most impactful with this trouble code is that it is common for there to be a decrease in fuel economy so the car will burn fuel at a higher rate of speed. For this reason, it is important to have a technician complete a diagnosis of the code, as well as making the necessary repair, as soon as possible.

What repairs can fix the P0134 code?

  • The technician should use a scanner to validate the fault code. After the fault code has been validated, it should be reset and a test drive should be performed. If the Check Engine Light returns with the same fault code, an inspection should follow.

  • The wires and connectors should be inspected for any damage. If the wires and connectors are damaged, they should be repaired or replaced. Reset fault code and test drive.

  • If the Check Engine Light comes on again and the technician gets the same code, the oxygen sensor will need to be replaced.

  • If the P0134 trouble code comes back after replacing the oxygen sensor, the exhaust pipe and heater fuse should be inspected to rule out possible damage of the two.

Additional comments for consideration regarding the P0134 code

Most commonly, the oxygen sensor itself will need to be replaced with a new one. However, before replacing the oxygen sensor, a problem with the wires and connectors should be ruled out.

It is important to reset the fault code and test drive the vehicle after repairing or replacing the wires, connectors, or oxygen sensor to see if the code comes back, before moving on to the next possible problem.

If the fault code still comes back after inspecting the wiring and/or connector(s) and replacing the oxygen sensor there are some less likely possibilities for getting this code. Some cars have a fuse for the oxygen sensor heater circuit and in this case, it is possible that the fuse has blown, although this is not common.

It is also possible that the exhaust pipe could have holes or excessive rusting. The last and least likely possibility for getting this code is that the power control module (PCM) is faulty and needs to be replaced.

Need help with a P0134 code?

YourMechanic offers certified mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

P0134
trouble codes
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0134 code.

SCHEDULE P0134 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating


YourMechanic Check Engine Light is on Inspection Service

Average Rating

4.8/5

Number of Reviews

5,583

Rating Summary
5,159
204
50
34
136
5,159
204
50
34
136

Matt

16 years of experience
35 reviews
Matt
16 years of experience
Jeep Compass - Check Engine Light is on Inspection - Holly Springs, North Carolina
Matt was awesome! Very knowledgeable, thorough. Really knows his stuff. Best part was his level of interaction and being able to ask him questions directly. You just don’t get that at the shops. Will definitely be using this service again and requesting Matt for all future jobs. Thanks again, Matt!

Matthew

32 years of experience
828 reviews
Matthew
32 years of experience
Land Rover LR2 - Check Engine Light is on - Hampton, Virginia
Matt is my go-to mechanic. Always professional and explains in detail what the problem is and how it’s being fixed. Highly recommend.

Richard

16 years of experience
115 reviews
Richard
16 years of experience
Honda Accord - Check Engine Light is on - San Ramon, California
Richard is Polite and skilled in inspecting the issues. I do recommend him for doing diagnostics before giving your car to the garage.

Michael

15 years of experience
565 reviews
Michael
15 years of experience
Chevrolet Avalanche 1500 - Check Engine Light is on - Marietta, Georgia
What professional handled himself well understood what was wrong with the car corrected it immediately and was on time


Related questions

P0134

Hi there, thanks for writing in. Code P0134 relates to the oxygen sensor -- something is wrong with this part. Normally the quick fix is just replacing the O2 sensor itself, however if this does not fix it, you may...

Failed emissions codes P0134, P0327, P3fff

The P0134 code means that the air fuel ratio sensor is not operating. Most of the time it will need replacing to correct. The P0327 code means that your knock sensor is not getting enough voltage. The P03FF may indicate...

Service Engine Soon light is on in 2003 Chevrolet Discovery

Code P0327 stands for knock sensor bank 1. Some of the common causes for this code are: a problem at connector C627 or C636, a problem with the power train control model (PCM) or a problem with the knock sensor...

More related articles

P0989 OBD-II Trouble Code: Transmission Fluid Pressure Sensor/Switch E Circuit Low
P0989 means there is an issue with the E circuit in the transmission fluid pressure sensor, likely due to a bad sensor, solenoid, or fluid level.
P2650 OBD-II Trouble Code: “B” Rocker Arm Actuator Control Circuit Open Bank 1
P2650 P2650 trouble code definition “B” Rocker Arm Actuator Control Circuit Open Bank 1 What the P2650 code means P2650 is an OBD-II generic code for the engine control module (ECM) detecting the B rocker arm actuator control circuit for...
P0163 OBD-II Trouble Code: 02 Sensor Circuit Low Voltage (Bank 2, Sensor 3)
P0163 P0163 code definition Trouble code P0163 is set when low voltage is detected on the bank 2 sensor 2 oxygen sensor circuit. What the P0163 code means Bank 2 refers to the side of the engine opposite of...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com