Network, generic

U0249 Lost Communication With Entertainment Control Module - Rear B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Rear B is the second rear entertainment unit; GM applies the code to a concrete part. Its 2011 Saab 9-5 code list names U0249 as lost communication with the rear radio audio control module, the rear seat audio controls with their own headphone outputs. On 2013–2014 Buick Enclave, Chevrolet Traverse and GMC Acadia the radio and the HVAC module stored U0249 within a long list of U codes when the side object sensor harness at the right rear rubbed through on the muffler and disturbed the LAN wiring; the cure was repairing and rerouting that harness (PI1202). The case shows that one chafed lead can silence modules far from the damage. Without unit B, rear audio controls, headphone sound or the second rear screen stop. Rear unit A is U0196, invalid data from B U054A.

Likely causes

Chafed or burnt network wiring elsewhere in the vehicle (GM: harness on muffler)
Rear unit without power or ground
Loose or corroded connector at the rear unit
Rear unit internally faulty

Symptoms

  • Rear audio controls or headphone outputs dead
  • Second rear screen without picture
  • Many U codes across modules, radio may switch off while driving

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–1,200
Time0.5–3 h

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

Parts involved

entertainment module rear bcan bus

Related codes

U0196U054AU0245U0497

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