P0136 – Meaning, Causes, Symptoms, & Fixes

Code P0136 Definition

O2 Sensor Circuit Malfunction (Bank 1, Sensor 2)

What Does P0136 Mean?

Your car has an Engine Control Module (ECM) which monitors your O2 sensor’s highest and lowest voltages. Depending on if your detected voltage is above or below what is acceptable, you can determine whether your car’s exhaust is running rich (voltage is too high) or lean (voltage is too low).If you are seeing code P0136, it means that the O2 sensor behind your  catalytic converter failed to meet its minimum and maximum voltage limit, as calibrated for you ECM to see.

P0136 Symptoms*

  • Check Engine Light
  • Possible exhaust leaks
  • Possible misfire
  • Poor fuel mileage

*No noticeable adverse conditions in some cases

P0136 Causes

  • Voltage limits not within specifications
  • Faulty 02 sensor
  • Exhaust leak or catalyst failure in front of sensor
  • Corrosion in connecter

Code P0136 Severity – Moderate   

Driving with trouble code P0136 is acceptable but only for a short period of time. Driving with this code for an elongated period of time could result in greater engine damage.

Code P0136 Common Diagnosis Mistakes

Replacing the O2 sensor without checking for any leaks or loose connections or for any voltage issues within the  O2 signal circuit.

P0136 Diagnosis

  • Tools Needed to Diagnose:

Difficulty of Diagnosis and Repair – (1-4)

  1. A sensor is needed for this next action, and the FIXD Sensor is perfect for it. Scan codes and document freeze frame data then clear codes to verify failure.
  2. Check live data from all 4 terminals of O2 sensors. Make sure the specific sensor’s (Bank 1, Sensor 2) voltage is not switching back and forth from high to low rapidly when compared to other sensors.
  3. Visually check O2 sensor wiring and harness for corrosion
    1. If corrosion is present, clean the corrosion from the connector
  4. Check for an exhaust leak in front of the sensor
  5. If these checks do not clear your Check Engine Light you may need to see a mechanic so they may conduct specific pinpoint tests, and possibly replace or repair your O2 sensor (Bank 1, Sensor 2).

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Comments 11


September 10, 2018

Needed diagnostic info for a similar (yet different) P0137 CEL code

FIXD Marketing

September 10, 2018

No problem Ryan! Here is a link for our article on Check Engine Light code P0137.


I dhandy

December 4, 2018

How much to replace all O2 sensor for 1999 ml 320 ?? Parts and labor ??

Danny mann

September 15, 2018

My car was running fine ,but check engine light was ,on b4 I got the car some one had a home made cold air intake on it ,I replaced it the other day with the proper one ,no air leaks etc,its properly but afterwards, car idles norm but will shut off sometimes when slowing and hesitating sometimes in 5th gear when at cruising speed 40/45 mph had it code checked and got PO137, OXY SENSOR BANK1 SENSOR 2 LOW VOLT, PO138 OXY SENSOR BANK 1 SENSOR 2 HIGH VOLT ,P1235 ,AND PO300 ,

Victor M Martinez

December 3, 2018

Please show me where is located the catalytic 02 sensor for my Dodge Ram 1500 2003 4.7 engine. Also need to now where is located the vacuum.

brian polidori

December 18, 2018

I’m getting this code, I have the FIXD app and device, I cleared the code, will I fail emissions test with this code popping up?

FIXD Marketing

December 18, 2018

Hello Brian,

If the code is emissions related, it cannot be cleared by a scanner. The light will come back on if the problem persists. It is recommended to have this code repaired as soon as possible as continuing to drive could risk greater damage to your vehicle’s engine.

I hope this helps!

Chris Allridge

April 19, 2019

I had a dirty mass air flow sensor that caused this error.


May 30, 2019

Where is the O2 sensor located on my Ford Escape 2003?
Many thanks

James Morris

June 7, 2019

Where are the 4 O2 sensors located on a 2013 Nissan Pathfinder?


June 11, 2019

PO137 Bank 1 SENSOR

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