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P2197 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P2197 is an OBD-II Code that refers to O2 Sensor Signal Stuck Lean – Bank 2 Sensor 1


A P2197 code is caused by an ECM (Engine Control Module) receiving a signal that the oxygen sensor on is not working within the parameters set by the manufacturer. It’s job is to tell the engine control module when there is too much oxygen in the exhaust. Too much oxygen in the exhaust will not allow the fuel system to maintain a proper air/fuel ratio during combustion, which leads to lean condition. When this happens the Engine Control Module (ECM) will store this code and will turn on the Check Engine Light.


Common causes for this code include:

  • Bad or Faulty O2 sensor
  • Short of O2 wiring harness
  • Exhaust leaks
  • Low fuel pressure
  • Mass Airflow Sensor Blockage
  • Faulty Fuel Injector


The symptoms of a P2197 code are:

  • The Check Engine Light comes on
  • The engine Temperature will rise
  • Rough running
  • Loss of engine power
  • Engine running lean
  • Misfires


To diagnose a P2197 DTC code, a technician would:

  1. Scan for codes in the ECM If a code other than P2197 is found, the problem should be diagnosed and repaired before moving on
  2. Inspect the wiring and connectors for O2 sensor and fuel injectors
  3. Perform a visual inspection of exhaust system for leaks or damage
  4. Inspect fuel pressure for fluctuations or lack of pressure
  5. Replace Mass Airflow Sensor if necessary
  6. Replace the oxygen sensor if needed
  7. Check the fuel pressure and pump

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P2197 code:

  • Not checking for faults in other components before fixing a P2197 code
  • Not using the proper scan tool for OBD-II codes
  • Not reading the ECM diagnostic trouble codes thoroughly
  • Forgetting to check for exhaust leaks/damage on visual inspection
  • Replacing oxygen sensor without replacing fuel injector when running lean on bank 2 only

How serious is this?

A P2197 code is considered to be serious enough that it can be potentially harmful to the vehicle if not diagnosed and resolved quickly. The reason for that is that running the engine lean will cause it to overheat and run poorly. If ignored for too long the engine could be damaged due to high operating temperatures.

What repairs can fix the code?

repair manuals

The following are solutions that may fix this problem:

  • Replacing a faulty O2 sensor
  • Replacing a faulty fuel injector
  • Repairing or replacing damaged or loose wiring and connectors that may be causing the code
  • Checking for exhaust leaks and repairing as necessary
  • Replacing the Mass Airflow Sensor if it is bad or causing problems

Related codes

A P2197 is related to and may be accompanied by the following codes:

P0107 – Mass or Volume Air Flow Circuit Low Input

P0300 – Random/Multiple Cylinder Misfire Detected

P1342 – Fuel Pump Relay Control Circuit High Voltage


In conclusion, the P2197 code is a generic trouble code that means the computer has detected an issue with the signal from the oxygen sensor. It is usually caused by a faulty O2 sensor, Mass Airflow Sensor, or fuel injector. In most cases this code is serious enough that it requires immediate attention but there are times when it can be ignored if there are no immediate symptoms.