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Home / DTC / B121C — Hard drive

B121C — Hard drive

Detailed page for trouble code B121C.

34,405codes
59brands
11,914generic
22,491specific
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Code

B121C

LAND ROVER B — Body

Hard drive

Brand: LAND ROVER
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Failed or degraded internal hard drive/SSD in the head unit
  • Corrupted file system or firmware on the drive
  • Intermittent or lost power supply (fuse, wiring, connector)
  • Poor ground connection to the infotainment module
  • Damaged or loose connector/cable between drive and head unit
  • Faulty infotainment/control module (controller electronics)

Symptoms

  • Navigation maps missing or fail to load
  • Infotainment system freezes, reboots or displays storage errors
  • ‘Hard drive’ or ‘Data error’ messages on screen
  • Slow or unresponsive media playback, missing radio presets
  • Loss of features that rely on internal storage (e.g., map updates)

What to check

  • Read complete freeze-frame and extended data with appropriate OEM diagnostic tool
  • Check for additional DTCs (U-codes or other B-codes) that indicate power or comms faults
  • Verify vehicle battery voltage and charging system health
  • Inspect fuses related to infotainment/navigation for continuity
  • Visually inspect connectors and wiring to the head unit and HDD/SSD (pins, corrosion, damage)
  • Check ground points for corrosion and tightness

Signal parameters

  • Supply voltage to head unit (nominal ~11–14.5 V)
  • Ground continuity and resistance to chassis
  • CAN bus activity and communication with navigation/head unit module
  • Module internal error counters or HDD SMART status (if available via diagnostic tool)
  • Presence/absence of HDD device enumeration or SATA/USB interface status (if supported)

Diagnostic algorithm

  1. Connect OEM-level diagnostic tool, read B121C and any related stored or pending codes; record freeze-frame and module data.
  2. Check battery voltage and ensure stable supply (perform tests with engine running and key on). Repair any low-voltage or charging issues first.
  3. Inspect and test fuses and relays for the infotainment/navigation circuits; replace any faulty items.
  4. Visually inspect connectors to the head unit and the physical HDD/SSD (if accessible). Reseat connectors and look for bent pins, corrosion or damage.
  5. Check ground connections for the head unit; clean and tighten as needed.
  6. If the diagnostic tool provides HDD/drive status (SMART or similar), review for errors. Note any drive not-present or read/write errors.
  7. Perform a controlled soft reset/reboot of the infotainment system. If available, run the head unit built-in self-test or diagnostics.
  8. If symptoms persist and wiring/power/grounds are good, attempt a software/firmware reflash or factory image re-install per OEM procedure (follow Land Rover service instructions).
  9. If reflash fails to resolve and diagnostics show drive hardware errors, replace the internal hard drive/SSD or replace the head unit as required. Ensure any replacement is programmed/configured and map/media data restored per OEM procedure.
  10. After repairs, clear codes, verify proper operation, and road-test to confirm the issue is resolved. Monitor for return of code.

Likely causes

  • Hard drive hardware failure (mechanical or electronic)
  • Corrupted navigation/media files or corrupted module flash
  • Poor 12 V supply or ground to the head unit
  • Connector pins damaged or mating connectors not fully seated
  • Module firmware/software anomaly requiring reflash

Fault status

⚠️ Status
Hard drive error detected in infotainment/navigation module — storage device not functioning or data corrupted (DTC B121C).
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.5-3.0 hours

Similar codes

B121A B121B B121D U0100 U0140
320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

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