P1031moderate severityPowertrain
Heated Oxygen Sensor Exchange Banks Swapped
on 2002 Mercedes-Benz SL 3.0L I6 · RWD
What this code means
The ECU detected that the upstream heated oxygen sensor connectors for Bank 1 and Bank 2 appear to be swapped. The sensor signals do not correspond to the expected bank, likely due to incorrect wiring after service.
Symptoms
- Check Engine Light
- Poor fuel economy
- Rough running
- Failed emissions test
Common causes
- O2 sensor connectors swapped after repair
- Wiring crossed between banks
- Incorrect sensor installation during service
Diagnostic steps
- Verify which O2 sensor connector goes to which bank
- Trace wiring from each sensor to ECU
- Induce a rich/lean condition on one bank and verify correct sensor responds
- Check sensor connector routing
Repair notes
Swap the O2 sensor connectors back to the correct bank positions.
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