What Does P1144 Mean?
This code indicates the Bank 1, Sensor 3 heated oxygen sensor signal is consistently above 0.45 volts, indicating a rich air/fuel ratio condition at the third sensor monitoring point. This suggests excess fuel or incomplete combustion products are reaching the rear portion of the exhaust system. The persistent high voltage can indicate a sensor fault, upstream rich condition, or catalyst degradation.
Common Causes
30%
Faulty HO2S Bank 1 Sensor 3 biased rich or contaminated
25%
Upstream rich condition carrying through to the rear exhaust monitoring point
20%
Deteriorated rear catalytic converter unable to fully oxidize remaining hydrocarbons
15%
O2 sensor wiring short to voltage or damaged insulation
10%
Oil or coolant contamination of the sensor element causing false rich readings
Diagnostic Steps
1
Monitor Bank 1 Sensor 3 voltage at steady cruise and compare to expected stable readings for the vehicle.
2
Review upstream fuel trim data and Sensor 1/Sensor 2 readings to determine if there is an overall rich condition on Bank 1.
3
Inspect the Sensor 3 for physical contamination (oily deposits, white residue from coolant).
4
Check the sensor wiring for shorts to battery voltage or damaged insulation near the exhaust.
5
Evaluate rear catalytic converter efficiency by comparing input and output gas composition if applicable.
Estimated Repair Cost
$100 - $400
Parts + labor, varies by vehicle and location
This code indicates the Bank 1, Sensor 3 heated oxygen sensor signal is consistently above 0.45 volts, indicating a rich air/fuel ratio condition at the third sensor monitoring point. This suggests excess fuel or incomplete combustion products are reaching the rear portion of the exhaust system. The...
The most common cause of P1144 (HO2S Bank 1 Sensor 3 Signal Above 0.45v (A/F Ratio Too Rich)) is: Faulty HO2S Bank 1 Sensor 3 biased rich or contaminated
Typical repair costs for P1144 range from $100 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
No direct safety hazard under normal conditions. Persistent rich exhaust at the rear of the system indicates the catalytic converters are not fully treating emissions, which affects air quality compliance but not vehicle operation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1144 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions / Catalyst Monitoring
Difficulty
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