Code Definition

B1378 — Oil Change Lamp Circuit Short To Ground

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

About B1378

B1378 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 B1378 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit.

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.

B1378 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 oil change lamp circuit is part of the body or instrument cluster control system that drives the maintenance reminder indicator on the dashboard. DTC B1378 sets when the controlling module detects a short to ground on the lamp control wire, meaning the circuit is being pulled to chassis ground at a time when the module is not commanding the lamp on. On platforms where the module switches the ground side of the bulb, an external short to ground bypasses the module driver and forces the lamp on continuously, while on platforms where the module supplies positive voltage through the lamp, a sh...

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