NHTSA Complaint #11130593 — 2015 FORD F-150

ENGINE ABRUPTLY DROPPED TO A ROUGH IDLE WITH NO THROTTLE RESPONSE WHILE IN TRAFFIC. DISPLAY CONSOLE REPORTED 'SERVICE ADVANCETRAC' AND OTHER WARNINGS. I MANAGED TO COAST TO THE SIDE OF THE ROAD. I SHUT OFF AND RESTARTED THE ENGINE AND WAS ABLE TO DRIVE NORMALLY. THE SAME SYMPTOM REPEATED THE NEXT DAY. THIS IS A REPEAT OF THE SAME SYMPTOM THAT OCCURRED AT ABOUT 17000 MILES. AT THAT TIME THE DEALER REPLACED THE THROTTLE BODY UNDER WARRANTY. THIS TIME THE VEHICLE WAS OUT OF WARRANTY, SO I REPLACED THE THROTTLE BODY MYSELF AND FIXED THE PROBLEM. I SUBSEQUENTLY DISASSEMBLED THE OLD THROTTLE BODY TO SEE IF I COULD IDENTIFY THE ROOT CAUSE OF THE PROBLEM. AS AN EXPERIENCED ELECTRONIC ENGINEER, I HAVE A BETTER SHOT AT DOING THIS THAN MANY. UPON DISASSEMBLY, I NOTICED BLACK DISCOLORATION ON THE CONNECTOR TO THE MOTOR THAT CONTROLS THE THROTTLE. THE MATERIAL OF THAT CONNECTOR APPEARS TO BE TIN OR A TIN ALLOY; THE BLACK IS LIKELY AN OXIDE THAT CAN CAUSE AN OPEN CIRCUIT. THIS LOOKS LIKE A PHENOMENON CALLED 'FRETTING' THAT CAN OCCUR IN CONNECTORS WHEN VIBRATION IS PRESENT. THE USUAL FIX IS TO CHANGE TO GOLD PLATED CONTACTS, AND/OR ENSURE CONTINUED LUBRICATION OF THE CONTACTS. I'VE ATTACHED AN ARTICLE ON 'FRETTING' FOR REFERENCE. BASED ON THE FACT THAT THIS PROBLEM WAS NOT PERMANENTLY FIXED BY THE FIRST REPLACEMENT OF THE THROTTLE BODY, IT APPEARS THAT FORD HAS NOT IMPLEMENTED A DESIGN CHANGE TO MANAGE IT. IT'S LIKELY THAT THE PROBLEM WILL RECUR AND REQUIRE REPEATED FIXES. THIS IS DANGEROUS IN TRAFFIC BECAUSE IT'S NOT ALWAYS POSSIBLE TO COAST TO A SAFE LOCATION WITH A NON-FUNCTIONING ENGINE.