Fault Family System: Chassis (C-Codes) 40 SAE Codes

AWD Transfer Case Differential Actuator Circuit

Diagnostic & Technical Explanation

Code C0071 (2/4 Wheel Drive Status Input) sets when the driveline control module cannot verify correct operation of a power-transfer unit, transfer case, or rear differential actuator -- the actuator's position sensor disagrees with commanded position, a temperature sensor reads out of range, the driveline module's own driver circuit fails, or a status input like the 2WD/4WD switch reports an implausible state. These electronically controlled units engage AWD/4WD by moving an internal clutch pack or range fork with a motor or solenoid actuator, so most faults trace to a failed actuator motor, a worn position sensor, low or contaminated differential fluid causing the actuator to bind, or a corroded connector on the underbody driveline harness. A vehicle stuck in one drive mode, a driveline clunk on engagement, or a warning message are the typical driver-facing symptoms. This family also covers codes naming the actuator's integrated position or temperature sensor circuit directly -- including the power-transfer unit and rear differential temperature sensor codes (C0093, C0094) -- since those sensors share the same connector and wiring diagnosis path as the actuator itself.

These 40 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 40 times.

Codes in this family (40)

Code	Definition	Repair coverage
C0071	2/4 Wheel Drive Status Input	4 ranked fixes
C0090	4WD/AWD Power Transfer Unit Actuator	4 ranked fixes
C0091	4WD/AWD Power Transfer Unit Position Sensor A	4 ranked fixes
C0092	4WD/AWD Power Transfer Unit Position Sensor B	4 ranked fixes
C0093	4WD/AWD Power Transfer Unit Temperature Sensor	4 ranked fixes
C0094	4WD/AWD Rear Differential Unit Temperature Sensor	4 ranked fixes
C0095	4WD/AWD Rear Differential Unit Actuator A	4 ranked fixes
C0096	4WD/AWD Rear Differential Unit Actuator A Data	4 ranked fixes
C0097	4WD/AWD Rear Differential Unit Actuator B	4 ranked fixes
C0098	4WD/AWD Rear Differential Unit Actuator B Data	4 ranked fixes
C0099	4WD/AWD Rear Differential Unit Actuator A Position Sensor A	4 ranked fixes
C009A	4WD/AWD Rear Differential Unit Actuator A Position Sensor B	4 ranked fixes
C009B	4WD/AWD Rear Differential Unit Actuator A Position Sensor C	4 ranked fixes
C009C	4WD/AWD Rear Differential Unit Actuator A Position Sensor Correlation	4 ranked fixes
C009D	4WD/AWD Rear Differential Unit Actuator B Position Sensor A	4 ranked fixes
C009E	4WD/AWD Rear Differential Unit Actuator B Position Sensor B	4 ranked fixes
C009F	4WD/AWD Rear Differential Unit Actuator B Position Sensor C	4 ranked fixes
C00A0	4WD/AWD Rear Differential Unit Actuator B Position Sensor Correlation	4 ranked fixes
C00A1	Driveline Control Module	4 ranked fixes
C00A2	Driveline Control Module Power Transfer Unit Control Circuit Driver	4 ranked fixes
C00A3	Driveline Control Module Rear Differential Unit A Control Circuit Driver	4 ranked fixes
C00A4	Driveline Control Module Rear Differential Unit B Control Circuit Driver	4 ranked fixes
C00A5	Driveline Control Module Transfer Case Unit Control Circuit Driver	4 ranked fixes
C00A6	4WD/AWD Transfer Case Unit Actuator	4 ranked fixes
C00A7	4WD/AWD Transfer Case Unit Actuator Position Sensor A	4 ranked fixes
C00A8	4WD/AWD Transfer Case Unit Actuator Position Sensor B	4 ranked fixes
C05F5	4WD/AWD Range Actuator Control Circuit/Open	4 ranked fixes
C05F6	4WD/AWD Range Actuator Control Circuit Performance	4 ranked fixes
C05F7	4WD/AWD Range Actuator Control Circuit Low	4 ranked fixes
C05F8	4WD/AWD Range Actuator Control Circuit High	4 ranked fixes
C05F9	4WD/AWD Range Actuator Temperature Too High	4 ranked fixes
C05FA	4WD/AWD Range Actuator Performance/Stuck	4 ranked fixes
C05FB	4WD/AWD Range Actuator Position Sensor Circuit	4 ranked fixes
C05FC	4WD/AWD Range Actuator Position Sensor Circuit Range/Performance	4 ranked fixes
C05FD	4WD/AWD Range Actuator Position Sensor Circuit Low	4 ranked fixes
C05FE	4WD/AWD Range Actuator Position Sensor Circuit High	4 ranked fixes
C05FF	4WD/AWD Range Actuator Position Not Learned	4 ranked fixes
C0600	4WD/AWD Range Actuator Position Control Error	4 ranked fixes
C0631	Front Axle Disconnect Actuator	4 ranked fixes
C0632	Front Axle Disconnect Control Circuit	4 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

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