O2 Sensor Signal Stuck Rich (Bank 2 Sensor 1)
What it means
This code is the same as P2196 but for the upstream oxygen sensor on bank 2. The engine computer has found that the sensor keeps reporting rich and does not respond when fuel is cut, either because that bank's cylinders really get excess fuel or because the sensor is contaminated or its wiring is faulty.
Symptoms4
- Check engine light on.
- Loss of performance and occasional stumbling.
- Fuel smell from the exhaust if the mixture is truly rich.
- Failed emissions test.
Possible causes5
- Bank 2 upstream oxygen sensor contaminated by oil, coolant or fuel.
- One or more leaking injectors on bank 2.
- Sensor signal wire shorted to a voltage source.
- Sensor failure from age.
- A shared cause such as high fuel pressure or a stuck purge valve if P2196 is also stored.
How to diagnose5
- Read all stored codes; P0175 or P2196 alongside it suggests real excess fuel or a shared cause.
- Compare the bank 2 sensor signal and fuel trims with bank 1.
- Test the sensor's response by briefly creating a vacuum leak; a good sensor swings lean immediately.
- Check the bank 2 injectors for leaks and measure fuel pressure.
- Remove the sensor and inspect its tip for deposits, and check its wiring.
How to fix5
- Repair shorted sensor wiring.
- Replace the purge valve or repair the pressure regulator if the cause is shared by both banks.
- Repair or replace the leaking bank 2 injector.
- Replace the bank 2 upstream oxygen sensor after fixing the source of contamination.
- Clear the codes and confirm the sensor responds normally.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
The cost is low for a wiring repair or purge valve, and rises when the sensor or injectors are replaced or the sensor is hard to reach.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
What does it mean if P2196 and P2198 appear together?
It usually means the cause is shared by both banks, such as high fuel pressure or a stuck purge valve, rather than two failed sensors at once.
Can I drive with this code?
Usually yes, but if the mixture is truly rich the catalytic converter can be damaged, so repair it soon.
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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.
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