P0041: O2 Sensor Signals Swapped — Bank 1 Sensor 2 / Bank 2 Sensor 2
What to do
Recent exhaust or catalytic converter work is the detail worth reporting; it usually explains this code outright.
What this code means
The same crossed-signal conclusion as P0040, drawn about the two downstream sensors. Because downstream sensors are physically similar and often carry identical connectors, they are easy to swap during exhaust work — check the routing of each harness back to its own bank rather than assuming the labels are right.
Likely causes
Start here
Less common
- Wiring harness repaired incorrectly · moderate
- Faulty oxygen sensor · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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