Network, generic

U0503 Invalid Data Received From Door Control Module D

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0503 is the invalid-data code for door control module D. It is rarely seen in published service material: Ford, the most visible user of lettered door modules, labels the latch controllers of its four-door electronic-latch cars E to H (DCME–DCMH, e.g. Mustang Mach-E), leaving D unused there. In a four-door car with one unit per door, D would typically be the last of the four, but that is not fixed. When a receiver gets D's lock, window or switch data and the content fails its checks, the code is stored; if the frames stop, U0202 follows. No manufacturer documents U0503 publicly. Expect a single door with an unreliable lock, window or interior switch rather than a car-wide fault.

Likely causes

Door control module D internally faulty or water-damaged
Broken data lead in the door harness grommet
Weak 12 V battery causing faulty frames during wake-up

Symptoms

  • One door not unlocking or locking with the others
  • Window switch on that door ignored

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–500
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

door control module d

Related codes

U0202U0502U0504

References: patents.google.com, static.nhtsa.gov.