P2210: NOx heater-sense connection is shorted to ground

P2210 is the low-circuit fault for the heater-sense path of the engine-out NOx sensor. The reviewed GM row identifies the connection as HTemp and describes a short to ground. It is distinct from the heater-control ground-short code, even though both concern the same sensor assembly.

Sense and control require different evidence

The HTemp path supports heater-resistance measurement. P2210 does not directly test NOx concentration or prove that the heater-control output is grounded. A generic heater-current measurement therefore cannot independently settle the specific sense-circuit diagnosis.

For Continental generation 3.5 sensors, the source notes an internal 1.5-second electrical-fault debounce used to identify the affected wire condition. The ECM then uses its own counter of 80 failures within 160 samples at a 25-millisecond task rate. These are distinct stages; the hardware-specific debounce must not be assumed for all NOx sensors.

Conditions and confirmation

Dewpoint must be reached, the NOx bus relay commanded on, relay voltage above 11 volts and sensor supply above 9.90 volts. Lost communication and invalid CAN-data faults are excluded. Reporting is Type B over two trips.

Verification should allow valid sensor reporting and controller qualification under those conditions, then confirm the HTemp ground-short status is absent. A no-result observation during communication loss or early warm-up is inconclusive. The page supplies no physical pin number or component-replacement instruction. Exact sensor generation, vehicle applicability and safe electrical access require the appropriate service information.

Source: GM monitor, PDF page 1417.