Code Definition

B2678 — Low Coolant Sender Failure

System: Body  |  Type: Generic (OBD-II Standard)  |  Make: Ford

About B2678

B2678 is a generic (obd-ii standard) 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 B2678 is stored, the module has detected a signal or supply voltage lower than the expected operating range.

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.

Because B2678 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The Body Control Module (BCM) or Instrument Cluster monitors the low coolant level sender circuit to determine engine coolant level status in the radiator overflow bottle or main expansion tank. DTC B2678 is set when the module detects an electrical fault or implausible signal from the low coolant sender, such as an open circuit, a short to ground, a short to voltage, or a signal that does not correspond with expected coolant level conditions over time. The sender is typically a float switch or thermistor probe in the coolant reservoir that closes or changes resistance when coolant drops below...

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