Powertrain
generic / SAE
P0140
O2 Sensor Circuit No Activity / Slow Response (Bank 1 Sensor 2)
The ECU detects no switching or excessively slow response from the downstream oxygen sensor on bank 1. Typical for an aged or poisoned sensor; downstream sensors should show a relatively flat signal but must respond to fueling changes during diagnostic monitor runs.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 40
Possible causes
- Sensor aged or poisoned high
- Sensor heater circuit weak medium
- Catalytic converter so degraded that downstream signal mirrors upstream low
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Inspection / repair
- Difficulty: easy
- DIY: possible
- Estimated cost: 80–350 €
- Estimated time: 0.3–1.5 h
- Component: oxygen sensor b1s2
- Component: oxygen sensor heater circuit
- Component: catalytic converter bank1
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012