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The oxygen sensors are essential to maintaining the ideal air/fuel mixture in your engine. They tell the powertrain control module (PCM) the amount of oxygen in the exhaust stream. Knowing the ratio of fuel to air enables the PCM to make any necessary changes to the engine’s air/fuel mixture.

The P2196 code is one of the engine codes that indicate an issue in the oxygen sensor. If left unresolved, it can cause drivability problems and diminish your engine’s performance. Read on to learn about its meaning, possible causes, common symptoms, and more.

What Does the P2196 Code Mean?

oxygen sensor near car engine
The P2196 code indicates an issue in the oxygen sensor between the catalytic converter and the engine.

Diagnostic trouble code (DTC) P2196 stands for “O2 Sensor Signal Biased/Stuck Rich (Bank 1, Sensor 1).” It is triggered when the PCM detects that the air/fuel ratio has deviated so far from the ideal proportions (14.7:1) that the PCM can no longer correct it.

The P2196 code indicates an issue in the oxygen sensor between the catalytic converter and the engine. Bank 1 refers to the side of the engine where the cylinder 1 is located.

P2196 is a generic OBD-II trouble code, so it is supported by various makes and models.

Fuel Trim and P2196

The PCM uses short fuel trim for instantaneous corrections. The O2 voltage trace has pronounced analog waves above and below 0.5 volts with the short fuel trim responding to each movement of the O2 waveform. But when short fuel trim reaches its limit, long fuel trim begins to apply adaptive learning to ratchet upwards until short fuel trim can return to the center of its scale. That’s why short fuel trim will usually be hovering on either side of zero while long fuel trim may be deep into plus or minus double digits.

In the case of a stored P2196 code, long fuel trim and short fuel trim are likely to be at their positive limit, indicating a seriously out-of-balance condition beyond the ECM/PCM’s adjustment range. In other words, the O2 sensor voltage will top out in the rich range and stay there.

What are the Possible Causes of the P2196 Code?

Electric socket wire connector to O2 sensor of engine
O2 sensor circuit problems, such as damaged wires and loose connections can cause the P2196 code.

Many issues can cause this code, and they may vary depending on your vehicle’s make and model. For example, the issues that can set a P2196 code in a Ford may slightly differ from the problems that can trigger a P2196 in a Hyundai. Here are some of the possible triggers of the code:

  • O2 sensor circuit problems, such as damaged wires and loose connections
  • Damaged/Failing O2 sensor (Sensor 1, Bank 1)
  • Rich condition due to a fuel system problem (e.g., faulty pressure regulator)
  • Saturated EVAP canister or other EVAP problems
  • Rich condition due to problems with other sensors, such as the mass air flow sensor
  • PCM issues

What are the Common Symptoms of the P2196 Code?

The most common symptom of the error code P2196 is an illuminated check engine light. However, take note that the check engine light can activate due to many other reasons. 

Here are some of the other symptoms related to a P2196 code:

  • Loss of engine power
  • Rough running and misfiring
  • Reduced fuel economy
  • Noticeable/Excessive smoke from the exhaust pipe

How to Diagnose the P2196 Code

Resolving this code can be challenging, as it involves accurately diagnosing the problem. If you are not confident that you can pinpoint what triggered the code on your own, it is best to leave the job to a certified mechanic.

However, if you think you’ve got the automotive DIY repair skills, here are videos you can watch to help refresh your knowledge on code P2196:

How to Fix the P2196 Code

The diagnostics and repair procedures for this code may vary depending on the vehicle’s specific make and model. It may be difficult to determine the right fix immediately, especially if you’re not familiar with auto repair.

Research confirmed fixes for the P2196 code that are specific to your car. Consult online auto repair resources and guides and don’t forget to check your owner’s manual before starting repairs.

Products Mentioned in this Guide

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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