P1130moderate severityPowertrain
HO2S Circuit Low Variance Bank 1 Sensor 1
on 2002 Mercedes-Benz SL 3.0L I6 · RWD
What this code means
The ECU detected that the upstream O2 sensor on Bank 1 is showing insufficient voltage switching (low variance). The sensor is not oscillating between rich and lean as expected during closed-loop operation.
Symptoms
- Check Engine Light
- Poor fuel economy
- Failed emissions test
- Slightly rough idle
Common causes
- Aging O2 sensor with slow response
- Exhaust leak before O2 sensor
- Fuel system issue masking sensor response
- Contaminated O2 sensor tip
- Wiring resistance issue
Diagnostic steps
- Monitor O2 sensor switching rate with scan tool
- Check for exhaust leaks at manifold
- Test sensor response to induced rich/lean condition
- Inspect sensor for contamination
- Check sensor wiring resistance
Repair notes
Replace the upstream O2 sensor on Bank 1 if response time has degraded.
Other Powertrain codes on this vehicle
P0001
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P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
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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