Chassis, generic

C00A3 Driveline Control Module Rear Differential Unit A Control Circuit Driver

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

C00A3 points to the driver stage inside the driveline module that powers actuator A of the rear differential unit, not to the actuator itself. The module's own transistor monitoring reports something wrong at that output. A Mitsubishi Electric patent illustrates the principle on an electromagnetic clutch: a PWM high-side and a low-side transistor feed the coil, the filtered terminal voltages are checked with the selector in P or N, and if they deviate from normal both transistors are switched off so the clutch opens. Modern H-bridge drivers such as TI's DRV8873-Q1 separately flag overcurrent, short to battery or ground, open load and overtemperature. On hydraulically actuated twin-clutch units, a dedicated ECU drives solenoid valves instead. No manufacturer publishes a C00A3 case; actuator A's own codes are C0095 and C0096.

Likely causes

Short to ground or battery in the actuator A supply lines
Actuator A motor or coil drawing excessive current (binding, winding short)
Output stage in the module overheated or defective

Symptoms

  • Rear clutch released, AWD inactive
  • AWD warning in the instrument cluster

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–1,300
Time0.5–4 h

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

Parts involved

driveline modulerear diff actuator a

Related codes

C00A1C00A4C0095C0096

References: patents.google.com, ti.com, mobilityengineeringtech.com.