P241A code meaning
O2 Sensor Signals Swapped (Bank 1 Sensor 1 / Bank 1 Sensor 2)
Powertrain system Generic code P24xx codes Check engine light
What P241A means
With P241A the engine controller has concluded that the oxygen readings of the sensor ahead of the bank 1 catalyst and of the sensor behind it fit the opposite mounting positions, so the two plugs or harness legs are most likely crossed. FCA uses the code on the 2011 Ram 2500/3500 with the 6.7L Cummins diesel and calls it an oxygen concentration mismatch between sensors 1/1 and 1/2; bulletin 18-012-12 Rev. A brings revised ECM software for it among other faults. CARB requires every sensor used for fuel control and catalyst checks to be monitored. P241B is the bank 2 pair, P2416 the pair behind the catalyst. In practice the code follows a sensor or exhaust repair; mixture control and catalyst diagnosis then work with wrong data.
P241A 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 P241A
- Check engine light after work on the exhaust or the oxygen sensors
- Mixture adaptation drifts, fuel trims look implausible
- Catalyst or sensor codes set as follow-up faults
Common causes of P241A
- Most likelyUpstream and downstream sensor plugs connected the wrong way round after a repair
- PossibleSensor harness rerouted or wrong replacement harness fitted
- Less likelyDetection software needing an update (FCA 6.7L Cummins)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor b1s1Oxygen sensor b1s2
What each part of P241A 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). |
| 1A | The exact fault in that area. |
What to do next
- Note P241A 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 P241A
What does P241A mean?
P241A means "O2 Sensor Signals Swapped (Bank 1 Sensor 1 / Bank 1 Sensor 2)". With P241A the engine controller has concluded that the oxygen readings of the sensor ahead of the bank 1 catalyst and of the sensor behind it fit the opposite mounting positions, so the two plugs or harness legs are most likely crossed. It is a generic code, so it means the same on every make.
Is it safe to drive with P241A?
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 P241A fail an emissions test?
Yes, it can. P241A 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 P241A 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 P241A 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.