Error Code P2098 is defined as Post Catalyst Fuel Trim System Too Lean Bank 2, a problem usually caused by issues in the catalytic converter or by an exhaust leak.

This code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system, especially vehicles made since 1996 up to present. Specifications on the definition, troubleshooting, and repairs, of course, vary from one make and model to another.


Error Code P2098 means the PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes) has determined that the signal voltage input coming from the downstream (post catalytic) O2 (oxygen) converter sensor has indicated that the O2 particle content is too high. The Bank 2o f the engine refers to the one that doesn’t have the number 1 cylinder.

O2 sensor is made up of a zirconium dioxide sensing element, enclosed within a vented steel housing. Platinum electrodes are attached to the sensing element to wire the leads to the O2 sensor harness connector. The CAN (controller area network) is connected to the O2 sensor wiring harness to the PCM. Post catalytic converter O2 sensor (for each bank) provides the PCM real-time data about the level of O2 particles in the engine’s exhaust in relation to the oxygen content of the air outside. This way (when used along with upstream O2 sensor) makes the monitoring of the catalytic converters more efficient.

If the reading from the post catalytic O2 sensor circuit input shows too many O2 molecules in the exhaust, once the PCM enters its closed loop operation, the Error Code P2098 will be stored to the vehicle’s memory, while simultaneously activating the Check Engine light.

Common Symptoms

As with other error codes, this code activates the Check Engine light and registers the Error Code to the vehicle’s memory as a fault after two trips completed back to back.

In many cases, the PCM will set itself into Failure Mode or Fuel Control mode, which means lean or rich drive symptoms, depending on the failure mode strategy of the manufacturer.

Other common driveability symptoms include:

  • Lack of general engine performance
  • Poor fuel efficiency

If the problem goes away, the engine will go back to its normal operation again, but will still keep the Check Engine light until the code is cleared from the memory.

In some cases, there may be some other related diagnostic trouble code stored along with P2098.

Possible Causes

Many factors lead to this code, such as:

  • Defective catalytic converter
  • Faulty O2 sensor(s)
  • Broken, burnt, chafed, or disconnected connectors or wirings
  • Exhaust leaks in the engine
  • Defective Mass Airflow or Manifold Air Pressure sensor

How to Check

To diagnose for this code, mechanics use the scan tool to scan for codes and document the code from the PCM, as well as the freeze frame data for the failure.

Then, they will scan the PCM to see if the O2 sensors are indicating problems on one or both sides of the engine. They will note to clear the code and get the engine out of failure mode fuel strategy.

Next, they check the engine for exhaust leaks, as well as any signs of damages in the wirings of the O2 sensor.

Lastly, they check the engine for other codes that may be present and causing the O2 sensors to fail.

How to Fix

Repairs for this code include:

  • Clearing the code and repairing the exhaust leak
  • Replacement of the Pre-Catalyst O2 sensor
  • Wiring repair
  • Damaged O2 sensor for both the pre and post catalyst must be replaced, which may have resulted from head gasket repair, or leaked coolant into the exhaust

This code means the PCM doesn’t have full control of the fuel as it should be since the O2 sensor is not giving the fuel control closed loop to control fuel correctly.

Other O2 related codes that are also related to Error Code P2098 are:

  • Error Code P1070 – Fuel Trim Malfunction (Bank 1)
  • Error Code P1071 – System Too Lean (Bank 1)
  • Or Any one of the O2 sensor codes for the engine bank in question