Troubleshooting a problem in a Subaru vehicle begins with identifying the affected system, then isolating the problem within the affected system, planning a suitable resolution for the problem, and carrying out the resolution. Subarus have the same major component systems as other vehicle brands, so the process of troubleshooting a Subaru is similar to that of other vehicle brands. Problems that are more common in Subarus than in other vehicle brands are the result of specific design details.
One of the most common reported problems with Subaru vehicles is a broken head gasket, a major engine trouble that is complicated to fix. This problem affects all models of Subaru and is especially prevalent in late 1990 and early 2000 models, according to Collins Automotive. This problem is indicated by oil or coolant leaks, frequent overheating, white exhaust smoke and a severe drop in engine power. Fixing a broken head gasket is a major repair job and one that is best undertaken by a professional mechanic.
Subarus made after 1995 have a computer called an ECM, or Engine Control Module. This computer has sensors throughout the car that can detect problems and report them as trouble codes through an OBD-II tool. OBD trouble codes can be a good indicator of system malfunctions in the power train or electrical systems. A list of Subaru OBD trouble codes can be found at OBD-codes.com. The details of connecting an OBD tool to a Subaru vary between models and are typically outlined in user manuals.