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Home / DTC / U0204 — Lost Communication With “Door Control Module F”

U0204 — Lost Communication With “Door Control Module F”

Detailed page for trouble code U0204.

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Code

U0204

HYUNDAI U — Network/User

Lost Communication With “Door Control Module F”

Brand: HYUNDAI
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in wiring between module and CAN bus
  • Corroded, loose or damaged connector at the Door Control Module F
  • Loss of module power or ground (fuse, relay, wiring)
  • Failed Door Control Module F (internal fault)
  • CAN bus fault elsewhere (short to battery/ground, poor termination, high resistance)
  • Software mismatch or module needing reflash

Symptoms

  • Loss of door-related functions (power locks, power windows, mirror folding, courtesy lights) or partial operation
  • Door-related errors or warnings on cluster or infotainment
  • Remote keyless entry or door unlock/panic not working for affected door(s)
  • Other modules reporting a module missing or CAN communication fault
  • Stored U0204 and possibly related U-codes in other modules
  • Intermittent operation that changes with door movement or vibration

What to check

  • Verify and record battery voltage (key ON) and charging system health
  • Scan all modules; note U0204 and any additional U-codes or related faults
  • Verify module presence on the network with a capable scan tool (attempt to communicate)
  • Visually inspect Door Control Module F connector and harness (look for corrosion, bent pins, water intrusion)
  • Inspect door hinge/boot area for chafed wires where harness flexes
  • Check relevant fuses and relays for module power and accessory power circuits

Signal parameters

  • Battery voltage at module connector: ~12 V (key ON)
  • Ground at module connector: ~0 V
  • CAN bus recessive voltages: CANH ≈ 2.5 V, CANL ≈ 2.5 V (differential ≈ 0 V)
  • CAN bus dominant voltages: CANH ≈ 3.5 V, CANL ≈ 1.5 V (differential ≈ 2.0 V)
  • Bus termination impedance between CANH and CANL ~60 ohms total (two 120 Ω in parallel)

Diagnostic algorithm

  1. Confirm and record the exact code and freeze frame/related codes from all modules
  2. Check battery voltage and charging; ensure stable supply (replace or charge if low)
  3. Use scan tool to try to communicate with Door Control Module F; note if module appears or is absent
  4. Inspect module connector and harness for mechanical damage, corrosion, water entry, and pin condition; repair as required
  5. Check module power and ground circuits (fuse, relay, continuity to battery/chassis) and repair any faults
  6. Inspect door harness at hinge/boot for chafing or broken wires; repair continuity/insulation as needed
  7. If harness and power/ground are good, check CAN bus at module plug: measure CANH/CANL voltages and compare to expected idle/dominant levels
  8. Compare bus behavior with another working node; check bus termination and measure resistance across CANH–CANL
  9. Perform wiggle/stress tests while monitoring for loss of communication to isolate intermittent wiring faults
  10. If wiring and CAN bus are confirmed good and power/ground are correct, suspect Door Control Module F hardware fault — consider module replacement or reprogramming per manufacturer procedure
  11. After repairs or module replacement, clear codes, re-initialize/reprogram module if required, and verify restored communication and door functions
  12. Document repairs and re-test in conditions that previously reproduced the issue

Likely causes

  • Damaged/loose connector at door control module
  • Open/shorted CAN bus wiring in door harness (pinch at hinge)
  • Blown fuse or missing module power/ground
  • Failed door control module
  • Corrosion or water damage in door harness

Fault status

⚠️ Status
U0204 — Lost Communication With “Door Control Module F” (no response on CAN network)
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

U0201 U0202 U0203 U0205 U0155 U0100
371

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