Before attempting repairs for SYNC 4 system, Telematics Control Unit (TCU) or Gateway Module (GWM) concerns, dealers must complete workshop manual (WSM) diagnostics in section 415-00 for SYNC 4 or TCU concerns and 418-00 for GWM concerns. Do not attempt APIM, TCU or GWM reprogramming or replacement unless directed by a WSM pinpoint test. If the root cause of a concern is isolated to the APIM, TCU or GWM with all other possible causes ruled out, dealers must contact the Technical Assistance Center prior to performing repairs.
