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U040E Invalid Data Received From Turbocharger/Supercharger Control Module B

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

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.

Likely causes

Electronics or position feedback of charger actuator B faulty

Connector or bus line of module B damaged by heat

Module B with software that does not match the engine controller

Symptoms

Check engine light
Reduced power, especially at higher load

Repair estimate

DifficultyHardWorkshop job

Parts and labour€150–1,800

Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

boost control module b

Related codes

U010D U040D P0234

References: law.cornell.edu, en.wikipedia.org.