Code Definition

B1438 — Wiper Mode Select Switch Circuit Failure

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

About B1438

B1438 is a manufacturer-specific body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1438 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.

B1438 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 body control module monitors the wiper mode select switch input from the steering column or instrument cluster wiper switch and sets DTC B1438 when it detects a circuit failure such as an open, short, or invalid voltage combination on the switch input lines. The wiper mode select switch is typically a multi position resistor ladder or discrete switched ground network that signals the BCM which mode the driver has selected (off, intermittent, low, high, mist, washer). When the BCM cannot read a valid switch position, it cannot select the appropriate wiper output. Symptoms include wipers tha...

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