What Does P2198 Mean?
The upstream oxygen sensor on Bank 2 is reporting a consistently rich air/fuel mixture that isn't responding to PCM corrections. This indicates the sensor is stuck reading rich or there's an actual over-fueling condition affecting Bank 2.
Common Causes
30%
Leaking or stuck-open Bank 2 fuel injectors
25%
Faulty Bank 2 Sensor 1 oxygen sensor (pre-cat)
20%
High fuel pressure due to failed fuel pressure regulator
15%
Contaminated or fouled oxygen sensor from oil/coolant consumption
10%
Mass airflow sensor reading incorrectly low or dirty
Diagnostic Steps
1
Step 1: Monitor Bank 2 O2 sensor voltage (stuck rich will show constant high voltage above 0.7V)
2
Step 2: Check fuel pressure with gauge and compare to specifications (should drop to spec when regulator vacuum applied)
3
Step 3: Perform Bank 2 injector balance test or measure injector resistance and compare between cylinders
4
Step 4: Inspect spark plugs from Bank 2 cylinders for carbon fouling indicating rich condition
5
Step 5: Check for intake air leaks after the MAF sensor or dirty MAF element causing incorrect readings
Estimated Repair Cost
$150 - $900
Parts + labor, varies by vehicle and location
The upstream oxygen sensor on Bank 2 is reporting a consistently rich air/fuel mixture that isn't responding to PCM corrections. This indicates the sensor is stuck reading rich or there's an actual over-fueling condition affecting Bank 2.
The most common cause of P2198 (O2 Sensor Signal Stuck Rich Bank 2 Sensor 1) is: Leaking or stuck-open Bank 2 fuel injectors
Typical repair costs for P2198 range from $150 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive short distances but will foul catalytic converter and spark plugs if continued. Expect poor fuel economy and potential misfires.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2198 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System / Emissions
Difficulty
Type
Generic (SAE)
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