P2101: Throttle position differs from its modeled response

P2101 is a throttle actuator position-performance fault in the reviewed GM monitor. The controller compares measured throttle position with a model derived from the commanded position and a filtered command. The comparison accommodates response dynamics; it is not simply a demand that every command and sensor value always match exactly.

Two documented checks

One check detects a difference greater than 10 percentage points between actual position and the appropriate modeled bound. The source counts 15 failures at a 12.5-millisecond evaluation interval. It also requires throttle control to be active, minimum-position learning to be inactive, and no P1682 powertrain-relay-contact fault.

A second check applies during minimum-position learning. The continuation page describes throttle position above 52.71% while that learning mode is active, with an 11-count criterion. This is a separate operating situation, so a code set during learning should not automatically be interpreted as a normal driving response error.

Diagnostic implications

Preserve whether learning was active when the fault appeared. That information determines which comparison is relevant and prevents a normal-operation recording from being mistaken for a reproduction of a learning-state failure.

The enable logic also depends on run/crank voltage and relay status, and excludes service or diagnostic throttle control. A commanded actuator test may therefore answer a different question from the onboard monitor. Review voltage and relay-related evidence before attributing every position discrepancy to the throttle body.

Use the applicable electronic-throttle procedure for verification; this summary does not support forcing the plate, bypassing safeguards or selecting a replacement assembly.

Source and applicability

This explanation is limited to the documented 2025 GM monitor; its thresholds are not universal vehicle specifications. GM diagnostic table, PDF page 594. GM diagnostic table, PDF page 595.