OBD-II code · Powertrain (generic)
P019A O2 Sensor Delayed Response - Rich to Lean Bank 1 Sensor 3
Bank 1 sensor 3 O2 sensor reacts only after delay during rich-to-lean transitions. A drifted or sluggish lambda sensor lets the mixture run lean or rich without correction — fuel economy and emissions suffer immediately.
Is it safe to drive with P019A?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySensor aged
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Oxygen Sensor B1s3
Related codes
- P013EO2 Sensor Delayed Response - Rich to Lean Bank 1 Sensor 2
- P014AO2 Sensor Delayed Response - Rich to Lean Bank 2 Sensor 2
- P015AO2 Sensor Delayed Response - Rich to Lean Bank 1 Sensor 1
- P015CO2 Sensor Delayed Response - Rich to Lean Bank 2 Sensor 1
- P019CO2 Sensor Delayed Response - Rich to Lean Bank 2 Sensor 3
- P0197Engine Oil Temperature Sensor Low
- P0198Engine Oil Temperature Sensor High
- P0199Engine Oil Temperature Sensor Intermittent
- P019BO2 Sensor Delayed Response - Lean to Rich Bank 1 Sensor 3
- P019DO2 Sensor Delayed Response - Lean to Rich Bank 2 Sensor 3
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.