P02E8: diesel throttle SENT position signal below range

P02E8 checks the electrical range of the diesel throttle's SENT position feedback in the documented system. The low threshold is a raw-position representation below 1% of the 5 V scale.

Signal range is not valve angle

The published quantity is a raw signal value, not a command that the throttle remain above 1% opening. A low-range fault makes the feedback suspect; it does not establish that the plate is mechanically closed or that insufficient intake air is the primary fault.

The monitor requires no throttle SENT communication-loss fault. That prerequisite separates a received but out-of-range signal from loss of the communications path itself. Establishing whether communication is healthy is therefore a useful first distinction when interpreting the code.

Conditions for a valid retest

Cranking must have ended, powertrain-relay supply must exceed 11 V and the test must be calibration-enabled. The source specifies 480 failed counts from 600 samples on a 6.25 ms task and Type A, one-trip reporting.

After a service correction, look for valid raw feedback during an eligible monitored period. A plausible displayed angle without knowing its source or validity is weaker evidence than a completed range check. The summary does not provide a connector pinout or identify a failed sensor independently of its circuit; use vehicle-specific SENT diagnostic information.

Source and applicability

2025 GM 25OBDG04B diagnostic parameter tables; the cited monitor only. Vehicle, engine and calibration applicability must be confirmed separately. These tables describe detection logic, not a complete repair procedure or a component replacement verdict. gm-2025-04b, PDF page 1167.