P0135 – Heated oxygen sensor (HO2S) 1, bank 1, heater control – circuit malfunction
Last Updated 2018-02-25
ASE Master Tech
|Code||Fault Location||Probable Cause|
|P0135|| Heated oxygen sensor (HO2S) 1, bank 1, heater control circuit malfunction |
(Buy Part On Amazon)
|Fuse, wiring, H025, ECM|
We recommend Torque Pro
Table of Contents
- What Does Code P0135 Mean?
- What are the common causes of code P0135 ?
- What are the symptoms of code P0135 ?
- How do you troubleshoot code P0135 ?
- Codes Related to P0135
- Get Help with P0135
What Does Code P0135 Mean?
The upstream oxygen sensor (O2S) is located ahead of the catalytic converter. It is used to determine the concentration of oxygen in the exhaust gas. This information is used by the PCM to control the engine air/fuel mixture. The sensor compares amount of oxygen in the exhaust to the surrounding air (there is an opening in the sensor that is exposed to the atmosphere). It generates a corresponding voltage which is transmitted to the PCM. The PCM then controls injector pulse based on this value.
Modern vehicles use a heated oxygen sensor (HO2S). These sensors contain a heating element that brings the sensor to operating temperature faster. This allows the PCM to use the signals input sooner, for more precise fuel control and reduced emissions. The heater circuit is energized through a relay that closes when the engine is cranked. The PCM monitors the heater circuit and will turn on the check engine light if it finds a problem.
Code P0135 stands for Oxygen O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1). This indicates the PCM has detected a problem with the bank 1 oxygen sensor. Bank 1 refers to the side of the engine that has the #1 cylinder. Bank 2 is the opposite side of the engine. If you’ve got a four-cylinder, there will only be one bank.
A typical heated oxygen sensor
What are the common causes of code P0135 ?
To sum things up, the common causes for code P0135 are as follows:
- Problem on the ground side of the O2 sensor heater circuit
- Problem on the power side of the O2 sensor heater circuit
- O2 sensor heater element has high resistance
- O2 sensor heater element has an open circuit
What are the symptoms of code P0135 ?
In theory, a failed O2 heater will result in poor fuel economy. But you’ll probably never notice the difference during operation. The only thing you will notice is an illuminated check engine light on your dashboard. If your registration is due, you will also fail the emissions test.
How do you troubleshoot code P0135 ?
This code can only be caused by problems in O2 sensor heater circuit, or by the sensor itself.
Typically, heated O2 sensors have four wires – two of which go to the heater circuit and two that are power and ground for the sensor. In this case study, we are only concerned with the heater circuit.
Typical O2 sensor heater circuit and connectors
You’ll want to obtain the wiring diagram from your vehicle to be certain you are testing the correct wires.
- Test the heater circuit wiring
First, you want to disconnect the O2 sensor connector and test the heater circuit for power and ground. You can do this using a digital multimeter.
By consulting the wiring diagram for you vehicle, determine which pin on the connector is power and which is ground. Set your multimeter to the volts setting. Touching the black multimeter lead to ground and the other to the power feed on the connector, you should see a reading that’s close to battery voltage. If not, you have a problem with the O2 sensor power supply. You’ll need to consult the power side of the wiring diagram to find where the circuit fault lies.
To test the ground side of the circuit, connect the red multimeter lead to the battery positive terminal and the black lead to ground. Once again, you should see a reading of about 12 volts. If not, you’ll need to consult the ground side of the wiring diagram to find where the circuit fault lies.
- Test the sensor heating element
If you’ve got good power and ground, the next thing to do is check the sensor heating element for either high resistance or an open circuit. You’ll do this using your digital multimeter.
Set your meter to the ohms setting. Then, connect your meter leads to both of the heater circuit pins on the sensor side of the connector. Consult the service information to see if the resistance value on your meter is within specification. If not, the heating element inside the sensor has high resistance and the sensor should be replaced.
If you get a reading that says OL on your meter while performing this test, the heating element has an open circuit. Once again, in this case, the sensor should be replaced.
Testing O2 heater element resistance
Codes Related to P0135
Code P0155 is the most closely related code to P0135. It stands for 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1). So, it is essentially the same code, but for the opposite bank of the engine. All of the same diagnostic steps apply.
Help Us Help You
Please comment below describing your issue as well as the specifics of your vehicle (make, model, year, miles, and engine), and one of our mechanics will respond as soon as possible. We appreciate a $9.99 donation via the payment button below.
Acura TLX 2015 donde está ubicado
Peugeot 206cc 2.0lt had engine light on and was getting half the normal mpg. Disconnected the second O2 sensor (after cat). The mpg is the best ever and the performance difference is amazing. Thinking about not even getting a new sensor the way it’s running at the moment
Oi bom dia amigo meu problema é o seguinte :tenho um festa 1997 e dura e apresenta código P0 135. Mas já troquei várias sondas lambidas mas sempre dá o mesmo defeito mesmo código de falha P0 135
I have a coja BMW n have been having issue of overheating with my car fr days now, I even went to d extend of changing d top sylinder gasget n yet same problem. I now remember I have a Obd scanner Wich I scanned n got P0135. How do my mechanic trace dis please?
The overheating problem and P0135 shouldn’t be related, but I’m thinking maybe the mechanic either didn’t connect the sensor again or broke a wire or the sensor itself.
My car is ford focus 2005, there is a lot of black smoke at the exhaust and consuming so much fuel. Diagnos PO135 02 S hearter circuit malfunction 1/1. Please what do I do?
У меня шевроле лачетти мкпп возникла проблема р0135 я менял датчик новый BOSCH все равно ошибка я не пойму . Прошу подскажите что делать?
I have a 2004 toyota avalon xls 3.0 i got a po135 code that indicates a fault in the bank 1 sensor 1 02 heater electrical circuit. Where is the location of this sensor and what should i do?
The sensor is in the exhaust system usually just before the catalytic converter. It will take a special tool that accommodates for the wires and the sensor for removal . Many parts places rent these for free. Due to their location it oftentimes requires a lot of force to remove them and they are also in difficult locations to get to. You cannot repair a sensor by cleaning or any method. There are people who have posted many methods of testing the sensors as they can be quite expensive.
My car is a 1999 toyota altezza 3sge automatic. It has no power whatsoever, its extremely sluggish to the point that trying to merge into traffic is dangerous, OBDII diagnostic brought out P0135 and P0155 codes. Want to know if that could be the culprit. Some mechanics are saying I should remove the catalytic converter. But then isnt sensor 1 the upstream sensor, so why would the catalytic converter even have any effect, if so
Did you find your problem. I’m having same issue, new o2 still same… very annoying
Yes, it could be. Replace both upstream O2 sensors, that will probably solve your problem. If you drive it too far you can also destroy your CAT and that can be really expensive.
Hello Guys, advice need please. I have a 2000 Toyota Sienna and it came up with the “P0135 – Heated oxygen sensor (HO2S) 1, bank 1, heater control – circuit malfunction” code.
What exactly am I supposed to do to please?
Is complete replacement the solution.
Thanks in anticipation.
If you can backprobe the oxygen sensor connector on the heater circuit while the engine is running, you should be able to see if there is voltage at the connector. If there is no voltage, then there’s likely an issue with the fuse or relay feeding the sensor (replacing the sensor won’t “fix” that). If there is voltage at the connector, then do a continuity check of the oxygen sensor heater circuit. Cold, the heater circuit should be 8-10 Ω. If your meter reads otherwise, this means the heater circuit is faulty. Replace the sensor if this is the case.
Where is the location for po135 on a 2006 GMC Envoy
You have to get a OBD2 code reader to see this code. Also it is a P0135, just to clarify. A good one can be expensive but many parts places will test for free. Some repair places (like Pep Boys) will also do it for free.