P2081: EGT sensor 1 changes faster than the monitor permits

P2081 is an intermittent-circuit code, but the reviewed GM implementation specifically checks rapid changes in exhaust-temperature sensor 1. The controller judges whether the signal changes faster than its expected dynamics, rather than waiting for a permanent open or short.

A change threshold, not an absolute temperature alarm

The malfunction criterion is an absolute raw-temperature difference greater than 100°C. Twelve failing samples within 25 qualify the condition on a 100-millisecond function task. This does not mean that any exhaust temperature above 100°C is a fault, and the table does not justify relabeling the threshold as a continuous degrees-per-second specification.

The source identifies internal sensor malfunction, deteriorated wiring and connector electrical issues as possible failure modes. It provides no probability ranking and does not establish which one caused an individual occurrence.

Conditions that distinguish a valid trace

The unfiltered temperature must lie between 140°C and 1,070°C. Cranking must be inactive, supply and Run/Crank conditions valid, diagnostics enabled and initialization complete. Relevant sensor electrical and communication faults must be absent.

Verification should observe the raw temperature changes inside that operating window and confirm the quick-change monitor completes without repeated excessive differences. A smooth processed display can be less informative than the raw signal used by the diagnostic. The table lists Type B, two-trip reporting. Exact probe identification and vehicle coverage remain service-information questions; this monitor summary is not a component-replacement instruction.

Source: GM monitor, PDF page 1393; GM monitor, PDF page 1394.