P241B code meaning
O2 Sensor Signals Swapped (Bank 2 Sensor 1 / Bank 2 Sensor 2)
Powertrain system Generic code P24xx codes Check engine light
What P241B means
P241B concerns only engines with a second exhaust bank, typically V engines: the controller has decided that the front and rear oxygen sensors of bank 2 deliver signals that belong to each other's position. No manufacturer bulletin names P241B publicly; the only published use of this check found is FCA's bank 1 version P241A on the inline-six Cummins, where it is described as an oxygen concentration mismatch. A frequent variant on V engines is not a swap within bank 2 at all, but a sensor plugged into the bank 1 harness, which is why P241A and P0041 deserve a look as well. CARB sets the monitoring duty for oxygen sensors. Until the wiring is right, fuel control and catalyst testing of bank 2 cannot be trusted.
P241B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1 hours
- Clears after repairAfter a drive cycle
Symptoms of P241B
- Check engine light shortly after work on bank 2
- Bank 2 fuel trims or catalyst monitor results implausible
Common causes of P241B
- Most likelyBank 2 sensor plugs swapped during a sensor or exhaust repair
- PossibleBank 2 sensor plugged into the bank 1 harness side
- Less likelySensor with the wrong type or cable length fitted
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor b2s1Oxygen sensor b2s2
What each part of P241B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 1B | The exact fault in that area. |
What to do next
- Note P241B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P241B
What does P241B mean?
P241B means "O2 Sensor Signals Swapped (Bank 2 Sensor 1 / Bank 2 Sensor 2)". P241B concerns only engines with a second exhaust bank, typically V engines: the controller has decided that the front and rear oxygen sensors of bank 2 deliver signals that belong to each other's position. It is a generic code, so it means the same on every make.
Is it safe to drive with P241B?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P241B fail an emissions test?
Yes, it can. P241B is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P241B to fix?
Difficulty: easy. A typical repair takes 0.3 to 1 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P241B clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.