P1131moderate severityPowertrain
HO2S Circuit Low Variance Lean Indication
on 2015 Volvo S80 3.0L turbocharged I6 (T6, 300 hp) · AWD
What this code means
The ECM detected that the upstream O2 sensor is showing a persistent lean-biased signal with insufficient switching activity. The sensor is stuck or sluggish on the lean side.
Symptoms
- Check Engine Light
- Poor fuel economy
- Rough idle
- Failed emissions test
Common causes
- Aging O2 sensor with degraded response
- Exhaust leak before O2 sensor
- Vacuum leak causing actual lean condition
- Contaminated O2 sensor
- Wiring issue affecting sensor output
Diagnostic steps
- Monitor O2 sensor signal switching with scan tool
- Check for exhaust leaks
- Perform smoke test for vacuum leaks
- Inspect O2 sensor for contamination
- Test sensor wiring
Repair notes
Replace the upstream O2 sensor if switching response has degraded.
🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
Budget handheld~$40
ANCEL AD410 →
No-phone-needed handheld — reads, clears, live data, freeze frame.
✓ ANCEL official store
Serious DIY~$100
BlueDriver Pro →
Enhanced codes (ABS, airbag, TPMS) plus repair reports.
SHOP FAVORITEShop-grade tablet~$300
Autel MaxiCOM MK808S →
Bidirectional tests, service resets, all systems.
✓ Autel official store
Pro diagnostics$1,500+
Autel MaxiSys MS906 Pro →
Full-system pro platform — topology mapping, ECU coding, the works.
✓ Autel official store
As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1