P2084: EGT sensor 2 has insufficient warming response after soak

P2084 is the sensor 2 counterpart of a post-soak exhaust-temperature response check in the reviewed GM system. The controller freezes a startup reference and compares it with the maximum temperature reached during a calibrated observation period. The failure is insufficient response relative to a mapped expectation.

Plausible temperature can still be unresponsive

The threshold map depends on the frozen temperature. As a result, a single fixed temperature-rise requirement cannot be extracted from this summary. A sensor can remain within its electrical range yet report too little change to be credible under the test conditions.

GM describes the monitor as capable of detecting a sensor outside the pipe or information stuck for another reason. That statement explains the test's purpose; it does not prove that the sensor has physically moved or establish a preferred replacement part.

Prerequisites shape verification

The controller requires a qualifying engine-off interval with a valid timer, followed by engine-running operation. Initialization must finish, diagnostics must be enabled, and the test must not have been aborted or already reported. Sensor 2 key-on, quick-change, high/low electrical and communication faults are excluded.

The row lists no extra debounce after the completed comparison and Type B, two-trip reporting. Verification should reproduce the permitted soak-and-response opportunity with sensor 2's prerequisites satisfied. A brief hot restart or a normal idle reading cannot independently prove the response check passed. These facts apply only to the documented 2025 GM monitor until the actual engine, probe arrangement and calibration are confirmed.

Source: GM monitor, PDF page 1395; GM monitor, PDF page 1396.