Description of On-Board Diagnostics
SELF-DIAGNOSIS DESCRIPTION1. When malfunction is detected in the electronic control system, the concerned parts and wires should be inspected individually. It takes a lot of time resulting in automotive engineers and drivers to inconvenience. To cope with it, computer detects the malfunctions and generates them as code so that engineer can troubleshoot easily.
2. Not all malfunctions of the vehicle are detected by Self-diagnosis. When the malfunction is completely presented like faulty parts of sensor or short/open wiring, detection will be easy. But when intermittent abnormality or short wiring occurs, self-diagnosis can't detect the errors even though the vehicle has problem.
3. The above 2 is caused by timing difference between outputs of input signal for controlling by computer and self-diagnosis. So while using self-diagnosis, be careful not to make a mistake.