What does it mean?
P1144 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: HO2S-22 (Bank 2 Sensor 2) Indicates A/F Ratio Too Rich (Self-Test) .
Symptoms
- Malfunction indicator lamp on with a strong fuel smell from the exhaust
- Black smoke, especially under acceleration or after a cold start
- Poor fuel economy and sooty deposits on the tailpipe
- Rough idle and occasional misfire-like stumble
- Spark plugs on that bank showing black, dry carbon
Likely causes
- Leaking or dripping fuel injectors on that bank adding unburned fuel
- Fuel pressure above specification because of a faulty regulator or a restricted return line
- Evaporative purge valve stuck open, dumping stored fuel vapour into the intake
- Contaminated or aged rear sensor giving a false high voltage reading
- Exhaust leak drawing in exhaust from another source, or a damaged catalytic converter releasing stored fuel
- Restricted air filter or a collapsed intake duct starving the engine of air
- Engine oil diluted with fuel, releasing vapour through the crankcase ventilation system
How to fix it
- Compare short and long term fuel trims on both banks; a strongly negative trim on Bank 2 confirms an actual rich condition
- Check fuel pressure at idle and with the vacuum line removed, comparing against specification
- Inspect the purge valve for leakage with the engine off, and check whether vacuum is present when it should be closed
- Perform an injector balance or leak-down check on that bank and inspect for wet spark plugs
- Examine the air filter and intake tract for restriction
- Look for exhaust leaks around the rear sensor and check the converter condition
- Replace the rear sensor only after the rich condition itself has been ruled out, then repeat the self-test