P1139: Front Oxygen AF Sensor #1 Heater Circuit Performance Range Problem
SUBARU
BMW
VOLKSWAGEN
BUICK
CADILLAC
CHEVY
CHRYSLER
FORD
Severity
Medium
System
Manufacturer-Specific Powertrain
What Does P1139 Mean?
P1139 is a manufacturer-specific diagnostic trouble code: Front Oxygen AF Sensor #1 Heater Circuit Performance Range Problem. This code applies to SUBARU, BMW, VOLKSWAGEN, BUICK, CADILLAC vehicles. Unlike generic OBD-II codes, manufacturer-specific codes are defined by the vehicle maker and may only apply to certain makes and models.
Symptoms of P1139
- β οΈ Check Engine Light (MIL) illuminated
- β οΈ Front Oxygen AF Sensor #1 Heater not meeting expected output
- β οΈ Degraded performance of related system
- β οΈ Reduced engine performance
Common Causes
- π Front Oxygen AF Sensor #1 Heater degraded from age or contamination
- π Mechanical wear in Front Oxygen AF Sensor #1 Heater or related parts
- π Restriction or blockage affecting Front Oxygen AF Sensor #1 Heater
- π Calibration drift in Front Oxygen AF Sensor #1 Heater
Frequently Asked Questions
What does P1139 mean?
P1139 indicates: Front Oxygen AF Sensor #1 Heater Circuit Performance Range Problem. The vehicle's computer has detected that the Front Oxygen AF Sensor #1 Heater is not operating within its expected parameters and stored this diagnostic trouble code.
Can I drive with code P1139?
You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1139 for extended periods may cause additional problems.
How much does it cost to fix P1139?
Repair costs for P1139 typically range from $50 to $400, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80β$150 at most shops) will identify the exact cause before committing to expensive parts.
What To Do Next
Possible Fixes
- π§ Inspect Front Oxygen AF Sensor #1 Heater for contamination or wear
- π§ Replace Front Oxygen AF Sensor #1 Heater
- π§ Address any related mechanical faults
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50β$150) pinpoints the root cause.
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