Code Definition

B2518 — Compressor Overtemp Fault

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

About B2518

B2518 is a generic (obd-ii standard) body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

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 B2518 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 HVAC controller monitors the air conditioning compressor temperature using a discharge line temperature sensor, a compressor body thermistor, or an inferred temperature calculation from refrigerant pressure and clutch duty cycle. DTC B2518 is set when the controller detects compressor temperature has exceeded the safe operating threshold, typically in the range of 130 to 150 degrees Celsius depending on the manufacturer specification. When the overtemperature condition is detected the controller commands the compressor clutch off (or de energises the variable d...

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