P2471: High-range exhaust temperature sensor 4 input

P2471 identifies a high-range input for exhaust-gas temperature sensor 4. In the cited monitor, high is interpreted according to the sensor arrangement. An analogue channel is checked as resistance, while a digital thermocouple channel is checked using its reported temperature.

Two representations of an electrical concern

The analogue branch lists resistance above 100 million ohms. The digital branch lists temperature above 1,289.85°C. These are separate raw-input criteria; the digital value alone is not proof that the exhaust physically reached that temperature. The source specifically frames the check as detecting electrical trouble, including module-to-probe harness issues in the digital arrangement.

The qualification is nineteen failed samples within twenty-five, at a 100-millisecond task interval. The row lists a one-trip response. Cranking, invalid supply, lost communication and an incomplete initialization delay can prevent an eligible evaluation.

Use the right data before deciding cause

Determine whether the vehicle uses the analogue or digital arrangement and preserve the relevant raw signal and validity state. A high resistance limit must not be applied to a digital communications line, and a temperature-display anomaly does not identify a failed probe without the appropriate tests.

The summary gives monitor thresholds, not connector access or circuit-isolation instructions. Follow the application's service procedure and allow safe exhaust-system conditions before physical work. Verification should confirm that the correct range check completes with valid input after initialization. A cleared code or one normal temperature sample does not establish that the repeated-sample fault has been resolved.

Source and applicability

2025 GM 04A documented monitor only; module and calibration applicability must be matched to the vehicle. GM PDF, page 1200.