U041D code meaning
Invalid Data Received From Rocker Arm Control Module B
Network system Generic code U04xx codes Check engine light
What U041D means
U041D is the counterpart for rocker arm control module B, used where the switching of rocker arms is split, for instance by cylinder bank. The code tells that the engine controller still receives B's messages, but their lift or lock status cannot be trusted. Comparing with U041C helps: B alone points to that module, its harness branch or its solenoids, both together to the shared supply or the bus. No manufacturer documents U041D publicly and no thresholds are known. CARB requires monitoring of variable valve lift and plausibility checks of digital inputs. Likely effects: MIL, cylinders on the B side held in full-lift mode, higher fuel use and perhaps rough running. U011C is lost contact.
U041D at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U041D
- Check engine light
- Uneven running or higher fuel use
Common causes of U041D
- PossibleSwitching solenoid or oil supply on the B side faulty
- PossibleRocker arm control module B internally faulty
- Less likelyShared supply or bus fault (then usually with U041C)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Rocker arm module bCAN bus wiring
What each part of U041D means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1D | The exact fault in that area. |
What to do next
- Note U041D 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 U041D
What does U041D mean?
U041D means "Invalid Data Received From Rocker Arm Control Module B". U041D is the counterpart for rocker arm control module B, used where the switching of rocker arms is split, for instance by cylinder bank. It is a generic code, so it means the same on every make.
Is it safe to drive with U041D?
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 U041D fail an emissions test?
Yes, it can. U041D 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 U041D to fix?
Difficulty: hard. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will U041D clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.