Powertrain
generic / SAE
P01F3
O2 Sensor Circuit High Voltage Bank 1 Sensor 4
Bank 1 sensor 4 O2 sensor signal voltage above expected range — short to power or sensor stuck high. A drifted or sluggish lambda sensor lets the mixture run lean or rich without correction — fuel economy and emissions suffer immediately.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / F3
Possible causes
- Signal wire shorted to battery high
- Connector pins corroded - high contact resistance low
- Supply wire pinched against B+ source low
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 80–400 €
- Estimated time: 0.5–2 h
- Component: oxygen sensor b1s4
- Component: sensor wiring
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012