2011 Chevrolet Camaro

GMC: UNABLE TO COMMUNICATE WITH THE EBCM DTC U0121. *NJ VEHICLES EQUIPPED WITH JL4. UPDATED 9/30/08. *PE UPDATED 6/27/11. *PE UPDATED 4/6/12. *PE

This Preliminary Information communication provides information to the technician the steps needed to diagnose and repair the vehicles that may have unwanted or phantom phone calls. Technician will need to determine what type of call the customer is having that is unwanted. The vehicle may receive an incoming call just like any other phone. Typically the customer will hear the phone ringing in the vehicle. This scenario also includes incoming Bluetooth calls. One type of unwanted call can be made if the key pad is faulty the OnStar system will try to make a blue button call for shorted voltage in the circuits. The OnStar module could have an internal fault and produce a ″Phone Unavailable″ audio message also it may have a Diagnostic Trouble Code U1500 or B1000. Refer to diagnostics for the Diagnostic Trouble Code making sure to follow any applicable Bulletins or Preliminary Information sheets. A “Ready” or “OnStar ready” audio message heard while driving. In some cases it has been found that the customer is inadvertently pressing the ″push to talk″ button on the steering wheel controls. On rare occasions, other issues in the steering column or Steering Wheel Control system may induce this concern.

This Preliminary Information communication provides information to the technician on how to diagnose and repair vehicles that may have an OnStar Turn-By-Turn Navigation the system that is inoperative. Technician verifies there are no Diagnostic Trouble Codes are present in the Antilock Braking System and Vehicle Communication Interface Module of the vehicle. If no Diagnostic Trouble Codes found call OnStar using the Blue button on the OnStar key pad and ask the advisor for a turn by turn route. Also make a OnStar personal call and a call into the vehicle. If normal diagnostics do not lead to a resolution technician will need to call General Motors Technical Assistance Center for further assistance.