Vehicle: 2014 Subaru Outback F4, 2.5L DOHC, Automatic Transaxle
Mileage: 62,009
Problem: The vehicle died while driving on the highway and was towed to the shop.
Details: When the vehicle was brought into the shop, the engine would crank over but not start. The tech checked fuses and found fuse #17 in the engine compartment had blown. When he tried another fuse, it immediately popped – there was a dead short to ground. He connected a scan tool to pull diagnostic trouble codes (DTCs) and found that there was no communication with PCM, but he could communicate with the TCM. He pulled DTC, U0100 – Lost Communication with ECM/PCM “A”.
The tech checked the W/R wire for a short circuit – it was good. He noticed that the main relay was not clicking on or off. After removing and reinstalling it, the relay began working properly.
Confirmed Repair: The tech replaced the main relay and #17 fuse, cleared the code and retested. The engine started right up and did not die on the test drive. When he checked again after the test drive for DTCs, there were none. Fixed.
The ALLDATA Tech-Assist team fields cases like this every day. See how Tech-Assist can help your shop save time and money with on-call diagnostic support from ASE-certified Master Technicians. More Tech Tips
Not an ALLDATA customer? For access to this valuable experience-based repair data and reliable OEM information, start a free trial today.
If you would like to read more articles like this one please subscribe to ALLDATA News.