What Does P2238 Mean?
The PCM detects abnormally low current in the positive current control circuit of the Bank 1 Sensor 1 air-fuel ratio sensor. This indicates the sensor's pumping cell is not drawing sufficient current.
Common Causes
50%
Failing wide-band oxygen sensor with degraded pumping cell
25%
High resistance in wiring harness or poor connector contact
12%
Low voltage supply to sensor due to charging system or PCM issue
10%
Corroded sensor connector causing high resistance
3%
PCM internal driver circuit malfunction
Diagnostic Steps
1
Measure battery voltage and charging system output to ensure proper voltage supply
2
Inspect sensor connector for corrosion, moisture, or damaged pins
3
Measure resistance in sensor wiring harness from connector to PCM
4
Using scan tool, monitor air-fuel ratio sensor current draw in live data
5
Replace air-fuel ratio sensor if all circuits test within specifications but current remains low
Estimated Repair Cost
$200 - $600
Parts + labor, varies by vehicle and location
The PCM detects abnormally low current in the positive current control circuit of the Bank 1 Sensor 1 air-fuel ratio sensor. This indicates the sensor's pumping cell is not drawing sufficient current.
The most common cause of P2238 (O2 Sensor Positive Current Control Circuit Low Bank 1 Sensor 1) is: Failing wide-band oxygen sensor with degraded pumping cell
Typical repair costs for P2238 range from $200 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive but air-fuel mixture may not be accurately controlled. Can cause rough running, reduced power, and poor fuel economy.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2238 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System and Emissions Control
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
