U041B code meaning
Invalid Data Received From Exhaust Gas Sensor Module A
Network system Generic code U04xx codes Check engine light
What U041B means
U041B names exhaust gas sensor module A, an electronic unit that heats and evaluates an exhaust probe, usually a wide-band oxygen sensor, and sends the result as bus data. The engine controller sets the code when the module still talks but its values fail plausibility, carry wrong counters or report the sensor as not ready. No manufacturer documents U041B publicly. Chrysler shows such a module on the Cummins 6.7 L in 2010-2012 Ram heavy-duty pickups: bulletin 25-002-14 lists its lost-communication code U011A among oxygen sensor faults and fits an overlay harness to the module before parts are replaced. CARB requires digital inputs of emission controls to be checked for out-of-range and rationality faults. Expect the MIL and closed-loop or aftertreatment functions held back. U046E is module B.
U041B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U041B
- Check engine light
- Higher fuel use or regeneration problems on diesels
Common causes of U041B
- PossibleHeat-damaged sensor harness or connector at the sensor module
- PossibleAged or contaminated probe giving implausible readings
- Less likelyExhaust gas sensor module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Exhaust gas sensor module aCAN bus wiring
What each part of U041B means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1B | The exact fault in that area. |
What to do next
- Note U041B 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 U041B
What does U041B mean?
U041B means "Invalid Data Received From Exhaust Gas Sensor Module A". U041B names exhaust gas sensor module A, an electronic unit that heats and evaluates an exhaust probe, usually a wide-band oxygen sensor, and sends the result as bus data. It is a generic code, so it means the same on every make.
Is it safe to drive with U041B?
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 U041B fail an emissions test?
Yes, it can. U041B 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 U041B to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U041B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.