Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2021 Ford Expedition XLT, 4WDFACTORY OEM SERVICE PROCEDURE
RHVAC Control Module
| DTC | Description | Action |
|---|---|---|
| B10B8:63 | Push Buttons: Circuit / Component Protection Time-Out | This DTC sets when the buttons are held too long. ATTEMPT to clean buttons. CLEAR the Diagnostic Trouble Codes (DTCs) and REPEAT the self-test. If the DTC does not return, IGNORE the DTC and CONTINUE diagnosing other Diagnostic Trouble Codes (DTCs) or symptoms. If the DTC returns, INSTALL a new RHVAC Control Module. Refer to REAR HEATING, VENTILATION AND AIR CONDITIONING (RHVAC) CONTROL MODULE |
| U0140:00 | Lost Communication With Body Control Module: No Sub Type Information | GO to Pinpoint Test W |
| U0164:00 | Lost Communication With HVAC Control Module: No Sub Type Information | GO to Pinpoint Test X |
| U0422:68 | Invalid Data Received From Body Control Module: Event Information | GO to Pinpoint Test W |
| U3000:41 | Control Module: General Checksum Failure | CLEAR the Diagnostic Trouble Codes (DTCs). WAIT at least 10 seconds. REPEAT the self-test. If DTC U3000:41 is retrieved again, INSTALL a new RHVAC Control Module. Refer to REAR HEATING, VENTILATION AND AIR CONDITIONING (RHVAC) CONTROL MODULE |
| U3000:42 | Control Module: General Memory Failure | CLEAR the Diagnostic Trouble Codes (DTCs). WAIT at least 10 seconds. REPEAT the self-test. If DTC U3000:42 is retrieved again, INSTALL a new RHVAC Control Module. Refer to REAR HEATING, VENTILATION AND AIR CONDITIONING (RHVAC) CONTROL MODULE |
| U3003:16 | Battery Voltage: Circuit Voltage Below Threshold | GO to Pinpoint Test Y |
| U3003:17 | Battery Voltage: Circuit Voltage Above Threshold | GO to Pinpoint Test Z |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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