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 Land Rover Defender 90FACTORY OEM SERVICE PROCEDURE
Diagnostic Trouble Code Index DTC: TELEMATIC Control Unit Module (TCU) -- Defender/L663
- Diagnostic Trouble Code Index - DTC: TELEMATIC Control Unit Module (TCU) (G2400918)
- Description And Operation
- TELEMATIC Control Unit Module (TCU)
- Notes
- DTC B10A2-12: Crash Input - Circuit short to battery
- DTC B10A2-14: Crash Input - Circuit short to ground or open
- DTC B10A2-38: Crash Input - Signal frequency incorrect
- DTC B116D-11: SOS On Call Keypad - Circuit short to ground
- DTC B116D-12: SOS On Call Keypad - Circuit short to battery
- DTC B116D-13: SOS On Call Keypad - Circuit open
- DTC B116D-97: SOS On Call Keypad - Component or system operation obstructed or blocked
- DTC B116E-11: SOS On Call Illumination - Circuit short to ground
- DTC B116E-12: SOS On Call Illumination - Circuit short to battery
- DTC B116E-13: SOS On Call Illumination - Circuit open
- DTC B116F-09: Telematics SIM Card - Component failures
- DTC B1179-04: Integrated GSM/GPRS Unit - System internal failures
- DTC B117A-01: Backup Microphone - General electrical failure
- DTC B117A-11: Backup Microphone - Circuit short to ground
- DTC B117A-12: Backup Microphone - Circuit short to battery
- DTC B117A-13: Backup Microphone - Circuit open
- DTC B119F-11: GPS Antenna - Circuit short to ground
- DTC B119F-12: GPS Antenna - Circuit short to battery
- DTC B119F-13: GPS Antenna - Circuit open
- DTC B14A9-13: BroadR-Reach Link - Telematics (+) - Circuit open
- DTC B14A9-64: BroadR-Reach Link - Telematics (+) - Signal Plausibility Failure
- DTC B14AA-13: BroadR-Reach Link - Telematics (-) - Circuit open
- DTC B14AA-64: BroadR-Reach Link - Telematics (-) - Signal Plausibility Failure
- DTC B14B5-11: WiFi Antenna #1 - Circuit short to ground
- DTC B14B5-12: WiFi Antenna #1 - Circuit Short To Battery
- DTC B14B5-13: WiFi Antenna #1 - Circuit Open
- DTC B15E3-54: Audio Calibration Parameter/Missing Calibration
- DTC B1A01-01: Speaker #1 - General electrical failure
- DTC B1A01-11: Speaker #1 - Circuit short to ground
- DTC B1A01-12: Speaker #1 - Circuit short to battery
- DTC B1A01-13: Speaker #1 - Circuit open
- DTC B1A56-11: Antenna - Circuit short to ground
- DTC B1A56-12: Antenna - Circuit Short To Battery
- DTC B1A56-13: Antenna - Circuit Open
- DTC B1D55-11: Antenna #2 - Circuit short to ground
- DTC B1D55-12: Antenna #2- Circuit Short to Battery
- DTC B1D55-13: Antenna #2- Circuit open
- DTC U0028-88: Vehicle communication bus A - Buss off
- DTC U0400-87: Invalid data received - Missing message
- DTC U2109-09: Back-up Battery - Component failures
- DTC U2109-91: Back-up Battery - Parametric
- DTC U3000-49: Control Module - Internal electronic failure
- TELEMATIC Control Unit Module (TCU)
- Description And Operation
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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