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U0204 Lost Communication With Door Control Module F

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0204 is set when door control module F stops answering. On the 2011 Saab 9-4x, whose U-code list comes from GM, the letter F belongs to the right rear door switch panel, the mirror-image partner of U0203 on the left. Before any repair, GM preliminary information PIC5741A (2013 Cadillac ATS, 2010–2013 SRX) is worth knowing: U0204, together with a long series of other communication codes and an instrument self-test, may appear only because the scan tool plug sits loosely in a diagnostic socket with spread terminals, most often ground pins 4 and 5. Checking and replacing those terminals comes first. With a genuine dropout, the window and lock switches at the right rear stop responding. No MIL is set.

Likely causes

Spread terminals in the diagnostic connector, false entries while testing (GM)
Broken wires in the right rear door hinge harness
Loose or corroded door connector pins
Rear door switch panel module faulty

Symptoms

  • Right rear window or lock switches inoperative
  • Codes appear together with an instrument self-test when the scan tool is plugged in

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–500
Time0.3–3 h

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

Parts involved

door module fcan bus

Related codes

U0203U0205U0505U0201

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