Powertrain, generic (extended)

P2176 Throttle Actuator A Control System - Idle Position Not Learned

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2176 says the closed rest position of throttle A could not be learned. At key-on or after shutdown the controller drives the plate onto its lower stop and stores the sensor values; if they stay outside the window after the permitted attempts, the code is set. GM's 2023 table 23OBDG07 aborts the learn when the plate misses the closed target by over 1.5 % or sensor 1 lies outside 0.33-0.58 V (sensor 2: 4.42-4.67 V), within one trip; GM's hybrid tables rate it Type A. Honda bulletin 13-042 cures false P2176 on 2013 Accord, Civic and Crosstour with software, GM PIP4573B blames frozen crankcase ventilation below -23 °C, and PIP4578B carbon. A Delphi patent describes repeated learn attempts. P218A is the throttle B code.

Likely causes

Carbon on plate and bore preventing a clean closed position
Ice from a frozen crankcase ventilation holding the plate open
Engine software misjudging the sensor signals (update available)
Idle learn not performed after cleaning or module replacement

Symptoms

  • Check engine lamp right after start
  • High, surging or unstable idle
  • Reduced engine power after a cold start

Repair estimate

DifficultyEasyDIY possible
Parts and labour€0–400
Time0.2–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

electronic throttle bodypowertrain control module

Related codes

P218AP2109P2119P0121P0506

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov.