Code Definition

B1840 — Wiper Front Power Circuit Failure

System: Body  |  Type: Manufacturer-Specific  |  Make: Ford

About B1840

B1840 is a manufacturer-specific body diagnostic trouble code recorded for Ford vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1840 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

B1840 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The B1840 fault code is set by the Generic Electronic Module (GEM) or Central Timing Module (CTM) when it detects a power circuit failure in the front wiper system. The front wiper motor receives switched power through a dedicated wiper power relay and protective fuse, with the module monitoring the supply circuit to confirm that voltage is present when the wipers are commanded on. When the module sees no voltage on the wiper power feed during a wiper request, or detects an out of range condition on this monitoring circuit, it stores B1840. The driver typically notices that the front wipers do...

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