P2417
O2 Sensor Signals Swapped Bank 2 Sensor 2 / Bank 2 Sensor 3
- Severity
- Low
- Driving
- Drivable — book it in
The module has worked out that the signals from sensors 2 and 3 on bank 2 have been swapped over. Each sits at a different point along the exhaust and should therefore behave differently - the one nearer the engine responds faster and runs hotter - so when those behaviours arrive on the wrong wires, the module can tell. This is a wiring mistake far more often than a component failure, and it usually appears immediately after exhaust or sensor work.
Possible causes
- CommonThe two sensor connectors plugged into each other's harness after recent work
- CommonSensors fitted into each other's positions in the exhaust
- PossibleRepair or extension harness wired the wrong way round
- PossibleAftermarket sensors whose connectors allow a mistake the originals prevented
- RareGenuine sensor fault making one behave like the other
What you might notice
- Check engine light on
- Failed emissions test
- Catalyst efficiency codes that do not make sense
- Usually no change in how the car drives
What to check, in order
- Find out what was done to the exhaust recently. This code rarely appears on a vehicle nobody has touched, and the answer is usually in the last job rather than in the wiring diagram.
- Trace both sensor harnesses physically from sensor to connector. They often run close together and are easy to cross, particularly where they pass behind a heat shield.
- Check the sensors are in the right holes as well as on the right plugs. Fitting them into each other's positions produces the same code as crossing the connectors.
- Do not simply clear this and move on. If the sensors really are crossed, the module is making fuelling and catalyst decisions on inverted information.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx