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U0509 Invalid Data Received From Seat Control Module A

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Seat control module A is usually the electronics of the first powered seat, often the driver's memory seat. The Saab 9-5 code list published by GM spells this out: there, the lost-communication partner U0208 is the memory seat control module. Its frames carry seat positions for memory recall, heating or ventilation states and switch inputs; when another controller receives them but finds them corrupted or implausible, U0509 is the result. Ford names its driver seat electronics DSM rather than by letter, so the A slot is not universal. No public bulletin covers U0509 itself. If the data is bad, memory positions may not recall, easy-entry movement may stop and climate seat functions may be shut off; driving is unaffected.

Likely causes

Seat module configuration or software not matching the vehicle
Under-seat harness or connector damaged by seat travel or objects
Seat control module A internally faulty

Symptoms

  • Seat memory positions not recalled
  • Seat heating or ventilation unavailable

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–500
Time0.5–2.5 h

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

Parts involved

seat control module a

Related codes

U0208U050AU0511

References: saabwisonline.com, static.nhtsa.gov.