Chassis, generic

C009C 4WD/AWD Rear Differential Unit Actuator A Position Sensor Correlation

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

Each of the three position channels of actuator A may look electrically fine, yet together they make no sense: a combination that cannot occur, a sequence that skips states or runs against the commanded direction. With 120-degree spacing the patterns 000 and 111 are invalid, as a Woodward patent notes. Ford is the only maker with a public case: SSM 50188 reports C009C in the AWD module of 2021 Bronco Sport vehicles alongside cluster messages: Service AdvanceTrac, unavailable Hill Start Assist or Pre-Collision Assist, a 4WD Malfunction notice and Reduced Power. Ford blames connector C413 being only partly engaged or having loose terminals, which should be ruled out before a new rear drive unit is fitted; otherwise the workshop manual section 307-07A applies. Hyundai Kefico separates open from shorted lines via all-low or all-high readings.

Likely causes

Rear drive unit connector not fully seated or loose pins (Ford C413)
Poor shared sensor ground or supply corrupting all three channels
Internal sensor or magnet fault in the rear drive unit motor

Symptoms

  • 4WD Malfunction message and AWD switched off
  • Service AdvanceTrac, hill start assist or pre-collision assist unavailable (Ford)
  • Reduced Power message

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–1,200
Time0.3–3 h

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

Parts involved

rear diff actuator a pos arear diff actuator a pos brear diff actuator a pos c

Related codes

C0099C009AC009BC00A0C0095

References: static.nhtsa.gov, patents.google.com, patents.google.com.