The presence of a Dodge check engine code or light means that the vehicle's diagnostic system has discovered a mechanical problem related to the engine's functioning or that of a related part. It is intended to supply the owner and mechanic with a starting point in prospective analysis and repair.
In formal terms, the check engine signal is considered part of a Dodge vehicle's "on-board diagnostics," a type of trouble-shooting system that first saw widespread implementation by many manufacturers in the 1980s. As with all manufacturer systems of this kind, individual codes are specific to Dodge vehicles only, and require specialized equipment to read. Usually, a decently equipped auto repair shop possesses the necessary scanning tool and or diagnostic computer. There are also cheaper, commercial models available for purchase.
Dodge engine codes span an enormously vast set of potential problems, including mechanical, structural, electrical or purely computer-related. For example, P1281 indicates lower than normal engine temperature, whereas PO455 indicates a large leak in the evaporator component of the vehicle. P1390 indicates that the timing belt is skipping, and P1684 warns that the battery has disconnected within the last 50 starts. Although some Dodge engine codes and warnings might appear and then disappear relatively quickly, it is still imperative that the owner have a mechanic examine the vehicle. Experts warn that long term avoidance of dealing with such code warnings ultimately ends up costing the consumer more money in repairs and component replacement.