Network, generic

U0501 Invalid Data Received From Door Control Module B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Many cars give each door its own electronics: a door unit receives commands over CAN and drives window lift, lock and mirror, as a Yazaki patent describes with a LIN sub-bus inside the door. Module A has its invalid-data code in U049A; U0501 is the same check for the second door unit. The body controller or another listener gets B's frames, for instance lock status, window position or switch inputs, but finds them implausible, out of sequence or with a bad checksum. Which door B serves is not standardised, and no carmaker documents U0501 publicly. GM's Saab 9-5 list, for one, has no partner entry U0200 for it. Silence from B gives U0200. The driver may notice one door that no longer locks centrally or whose window switch is ignored.

Likely causes

Water ingress into the door module through a failed door membrane
Broken wires in the harness grommet between body and door
Door module not programmed or configured after replacement

Symptoms

  • One door not following central locking
  • Window, mirror or door-ajar display of that door erratic

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 b

Related codes

U0200U049AU0502

References: patents.google.com, saabwisonline.com.