U040E code meaning
Invalid Data Received From Turbocharger/Supercharger Control Module B
Network system Generic code U04xx codes Check engine light
What U040E means
U040E is reserved for a second charger control module, B, on engines that run two separately actuated chargers: twin or sequential turbo layouts, or a turbocharger combined with an electrically driven or clutched supercharger. The engine controller sets it when module B's position or status messages keep coming but are judged invalid. No manufacturer documents U040E publicly, the NHTSA bulletin index has no entry, and thresholds are unknown. A useful check in the workshop is whether U040D is also stored: if only B is affected, its own actuator, connector and line are the first suspects, whereas both together point to the shared bus or the controller. With one charger unverified, boost and torque are usually limited and a MIL is likely, as CARB treats boost control as emission-relevant. U010D is lost contact, U040D module A.
U040E at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U040E
- Check engine light
- Reduced power, especially at higher load
Common causes of U040E
- PossibleElectronics or position feedback of charger actuator B faulty
- PossibleConnector or bus line of module B damaged by heat
- Less likelyModule B with software that does not match the engine controller
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Boost control module b
What each part of U040E means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 0E | The exact fault in that area. |
What to do next
- Note U040E 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 U040E
What does U040E mean?
U040E means "Invalid Data Received From Turbocharger/Supercharger Control Module B". U040E is reserved for a second charger control module, B, on engines that run two separately actuated chargers: twin or sequential turbo layouts, or a turbocharger combined with an electrically driven or clutched supercharger. It is a generic code, so it means the same on every make.
Is it safe to drive with U040E?
Drive gently and only to a workshop. With U040E the car can go into limp mode (reduced power) to protect itself.
Will U040E fail an emissions test?
Yes, it can. U040E 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 U040E to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will U040E clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.