C038D on 2007-2020 GMC Yukon — Range Actuator Position Not Learned
1 vehicles · 1 makes · $150-$700 repair
Most Reported On
C038D is an OBD-II diagnostic trouble code meaning “Range Actuator Position Not Learned.” C038D is a General Motors chassis code set by the transfer case control module (TCCM) on electronic-shift four-wheel-drive trucks and SUVs. It is an internal programming/calibration fault with no external circuit involved: the module has not stored the learned range actuator positions and clutch stack-up tolerance it needs to know where the actuator actually is. It sets automatically any time the TCCM or the range actuator/encoder motor assembly is replaced or reprogrammed without the range actuator relearn (high/low clutch reset) being performed. The driver usually gets a "Service 4WD" message and the transfer case may refuse to shift between 2HI, 4HI, and 4LO. This code is most commonly reported on 2007-2020 GMC Yukon, with repair costs ranging from $150 to $700.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
This is a chassis code. A basic engine-code reader will not show it — you need a scanner that reads chassis modules. These read C038D.
One caveat that applies to every scanner: only powertrain codes are standardised across manufacturers. Body, chassis and network coverage is "enhanced" diagnostics, and how deep it goes varies by make and model year — check your specific vehicle against the tool's coverage list before buying.
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Shop-level tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
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- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
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FAQ
What does C038D mean?
C038D stands for "Range Actuator Position Not Learned." C038D is a General Motors chassis code set by the transfer case control module (TCCM) on electronic-shift four-wheel-drive trucks and SUVs. It is an internal programming/calibration fault with no external circuit involved: the module has not stored the learned range actuator positions and clutch stack-up tolerance it needs to know where the actuator actually is. It sets automatically any time the TCCM or the range actuator/encoder motor assembly is replaced or reprogrammed without the range actuator relearn (high/low clutch reset) being performed. The driver usually gets a "Service 4WD" message and the transfer case may refuse to shift between 2HI, 4HI, and 4LO.
What are the most common causes of C038D?
The most common causes of C038D are: TCCM replaced or reprogrammed without performing the range actuator relearn procedure, Encoder motor / range actuator assembly replaced without a relearn, Relearn procedure attempted but not completed successfully with a capable scan tool, Failed or interrupted TCCM software update (SPS programming), Damaged, bent, pushed-out, or corroded connector pins at the TCCM or encoder motor, Faulty encoder motor position sensor or low battery voltage preventing the learn from completing. The specific cause varies by vehicle.
How much does it cost to fix C038D?
Repair costs for C038D range from $150 to $700, depending on the vehicle and root cause.
Which vehicles are affected by C038D?
Au7o has documented C038D across 1 vehicle models from 1 manufacturers: GMC.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.