P2211: NOx heater-sense circuit has a short-to-power indication

P2211 is the heater-sense circuit-high code for NOx sensor 1 in the reviewed GM system. The table names the resistance-measurement connection HTemp and defines the failure as a short toward power. It does not mean that the NOx concentration or the heater's operating temperature is necessarily high.

The reporting path has two stages

The controller counts 80 failing samples within 160 on a 25-millisecond task. The source separately notes that Continental generation 3.5 sensors use an internal 1.5-second debounce to identify electrical wire faults. That hardware-specific processing is not interchangeable with the controller sample window.

A brief status snapshot immediately after a change may therefore precede a fully qualified result. Equally, the internal debounce should not be generalized to an unidentified replacement sensor merely because it uses the same DTC.

What allows verification

The NOx bus relay must be on, powertrain-relay voltage exceed 11 volts and sensor supply exceed 9.90 volts. Dewpoint must be reached, while communication-loss and invalid CAN-data faults must be absent. Reporting is Type B across two trips.

Verification should confirm the HTemp power-short diagnosis completes without recurrence after those prerequisites are met. A clean heater-control test is useful separate evidence but does not prove that the sense connection is healthy. The source provides no physical terminal assignment, component location or repair verdict. These facts remain bounded to the documented 2025 GM monitor until exact sensor hardware and vehicle applicability are established.

Source: GM monitor, PDF page 1418.