P2080: EGT sensor 1 fails to show the expected post-soak rise

P2080 is a range/performance code for bank 1 exhaust-temperature sensor 1. In the reviewed GM strategy, it is a response test after a qualifying engine-off soak. The controller compares a later maximum temperature with a frozen startup reference rather than merely checking a high or low electrical limit.

Too little change can fail

The permitted difference comes from a calibration map based on the reference temperature. If the measured rise is below that mapped expectation, the monitor detects inadequate response. The source identifies a sensor outside the exhaust pipe or a stuck information value as failure modes this strategy can recognize; those are possibilities, not a diagnosis of the particular vehicle.

Because the limit is mapped, the page does not support one universal required temperature rise. An apparently reasonable static temperature reading can still fail if it does not respond as expected after startup.

What makes the test valid

The engine-off timer must be trustworthy, the subsequent engine-running conditions valid and sensor initialization complete. Communication loss, electrical high/low, quick-change and key-on faults are excluded, and the test must not have been aborted or already reported.

The row lists no additional debounce once its comparison is complete and Type B reporting over two trips. Verification must provide the qualifying soak and subsequent response opportunity; a warm restart alone does not recreate the monitor. This source does not provide a complete road-test recipe, a repair recommendation or exact vehicle coverage. Confirm the installed EGT system before applying its calibration-specific behavior.

Source: GM monitor, PDF page 1391; GM monitor, PDF page 1392.