P2207: NOx sensor 1 heater circuit short toward power

P2207 is the high-circuit code for the engine-out NOx sensor heater. The reviewed GM source consistently describes a short toward the power supply, but its strategy text calls the affected connection the heater supply pin while the malfunction cell calls it the heater control pin. This article does not silently choose a physical terminal from that conflicting wording.

What the code does establish

The supported failure category is a heater-circuit power short. It is not an elevated NOx concentration measurement or a direct temperature-overheating diagnosis. The row provides no numeric external voltage threshold or pinout with which to resolve the connection naming.

The monitor requires the sensor's dewpoint condition, a commanded-on NOx bus relay, powertrain-relay voltage above 11 volts and sensor supply above 9.90 volts. Lost communication and invalid CAN-data faults must be absent.

Qualification and verification

GM lists 80 failures within 160 samples on a 25-millisecond task, with Type B reporting across two trips. A brief key-on observation before dewpoint eligibility does not necessarily repeat the check, and a communication fault can prevent a usable result.

Verification should establish that the enabled heater power-short diagnosis completes without recurrence. Before probing or selecting a component, resolve the supply-versus-control pin wording through the applicable vehicle schematic and service diagnostic. The source does not establish a replacement decision or exact model coverage. This specific pin-description conflict remains documented for source review.

Source: GM monitor, PDF page 1412.