Network, generic

U050B Invalid Data Received From Moveable Roof Control Module B

Check engine lightUsually off

EmissionsNot relevant

Drive cycleNot required

Limp modeNo

A second moveable roof module only makes sense where the roof has more than one powered element, for instance a sliding front glass panel plus a separately driven rear panel or sunshade, or a large panoramic roof split into sections. U050B records that data from this second unit reached the network but was unusable. GM's Saab 9-5 code list knows only one moveable roof module (U0207), and no manufacturer publishes a case for the B module, so the code is uncommon. Its lost-communication partner is U020A. Because each panel keeps its own end positions and pinch protection, faulty data from B usually affects only that panel: it may stay closed, stop part-way or need re-initialising.

Likely causes

Second roof drive lost its end-position learning

Moveable roof control module B faulty, often after water entry

Connector or lead to the rear roof drive damaged

Symptoms

Rear roof panel or shade not moving while the front one works
Panel stopping part-way

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€0–700

Time0.5–3 h

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

Parts involved

moveable roof module b

Related codes

U020A U0508

References: en.wikipedia.org, saabwisonline.com.