C00A5

Code

Generic C — Chassis

Driveline Control Module Transfer Case Unit Control Circuit Driver

Brand: Generic

Type: C — Chassis

Views: UK: 19 EN: 27 RU: 23

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Page language: EN

Causes

Open or short in transfer case control wiring (power, ground, signal)
Corroded, loose or damaged connector at transfer case actuator or module
Failed transfer case actuator/solenoid or driver transistor inside driveline control module
Poor battery/ignition supply voltage or intermittent power loss
Loss of communication between driveline control module and vehicle networks
Software/firmware fault or calibration issue in the driveline control module

Symptoms

Malfunction Indicator Lamp (MIL) or drivetrain warning illuminated
4WD/AWD system disabled or stuck in one mode
Transfer case will not shift between modes or engages intermittently
Unusual noises from transfer case during shifting
Stored driveline/transfer case related codes and possibly limp-home behavior
Relevant functions in vehicle may be unavailable or limited

What to check

Use a diagnostic scanner to read all stored/active codes and freeze frame data; note mileage and conditions
Check for related network communication codes (U-codes) that may indicate module communication loss
Visually inspect wiring harness and connectors at driveline control module and transfer case actuator for corrosion, damage, or water intrusion
Check battery and charging system voltage (should be ~12.4–14.7 V) during tests
Back-probe connector pins with key on/engine running and wiggle harness to reproduce fault
Measure continuity and resistance between module connector and actuator (inspect for opens/shorts)

Signal parameters

Driver output when inactive: ~0 V (low) or open-circuit depending on design
Driver output when active: switched to battery voltage (~12 V) or PWM duty from 0–100% depending on actuator type
PWM frequency (typical range): 10–200 Hz (vehicle-specific)
Control signal reference: 5 V reference present on sensor/position circuits (typical)
Transfer case actuator coil resistance (typical range): 5–50 ohms (vehicle-specific)
Ground continuity: module ground to chassis < 1 ohm

Diagnostic algorithm

Capture stored codes, freeze frame and vehicle conditions with a scan tool. Record occurrence count and lamp status.
Inspect harnesses and connectors at the driveline control module and transfer case actuator for corrosion, damage, or signs of water ingress. Repair/secure as needed.
Verify battery and charging voltages. Poor supply can cause driver faults—repair charging/battery issues before further tests.
With connector connected, use scan tool to command transfer case actuator while observing live data. Note whether commanded state matches actual actuator response.
Back-probe the driver output circuit at the module while commanding the actuator. Verify expected voltage or PWM duty; wiggle harness to check for intermittent faults.
Measure actuator coil resistance with connector disconnected. Compare to specification range; replace actuator if open/shorted or out of range.
Check power feed and ground circuits to the module for continuity and correct voltages; inspect fuses and relays.
If wiring and actuator check OK but driver output is abnormal (stuck high/low or opens), suspect internal driver failure in the driveline control module—verify by checking for similar failures on other outputs if applicable.
Check for relevant software updates or calibrations; perform module reprogramming if manufacturer bulletin recommends.
After repairs, clear codes, perform actuator function tests and a road test under conditions that previously set the code. Re-scan to confirm the issue is resolved.

Likely causes

Damaged harness between driveline control module and transfer case actuator
Water-corroded connector at the transfer case actuator
Failed transfer case actuator coil or internal short
Faulty ground or fused power feed to the driveline control module
Intermittent module driver transistor failure

Fault status

⚠️ Status

Transfer case control circuit driver fault (C00A5). Driveline Control Module detected abnormal transfer case driver output. 4WD/AWD may be disabled. See dealer/service manual.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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