📖 What Does P0138 Mean?
The downstream oxygen sensor on bank 1 is reading consistently high voltage.
Symptoms
Failed emissions test, check engine light, rich running condition indication.
Common Causes
Faulty oxygen sensor, fuel system running rich, wiring short to power, contaminated sensor.
Possible Solutions
Replace oxygen sensor, diagnose rich fuel condition, repair wiring shorts, clean sensor area.
Recommended Parts & Tools
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📦 Parts Needed
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Frequently Asked Questions about P0138
How serious is P0138?
This code has a medium severity level. This should be diagnosed and repaired soon to prevent further issues.
Can I drive with P0138?
You can typically drive short distances, but have it diagnosed as soon as possible.
How much does it cost to fix P0138?
Repair costs vary depending on the root cause, but typically range from $100-300 including parts and labor.
Related Diagnostic Codes
Other codes that may appear with P0138
Fuel and Air Metering Code P0100
Mass Air Flow Sensor Circuit Range/Performance Problem
Mass Air Flow Sensor Circuit Low Input
Mass Air Flow Sensor Circuit High Input
Fuel and Air Metering Code P0104
Fuel and Air Metering Code P0105
💡 Why These Codes Are Related:
- • Similar Issues: Same root cause or component failure
- • Related Problems: Often occur together due to system interactions
- • Sequential Codes: Progressive failure stages or multiple sensors
- • Same System: Components within the same automotive system