What is the DTC status bit

What is the DTC status bit

The DTC status bit, StatusOfDTC, is used to indicate whether the fault corresponding to the DTC has occurred, whether it has been confirmed, etc. The DTC status bit contains 1 byte of data length, and each bit has a specific definition, as shown below:

However, not every bit must be used, depending on the needs of each OEM. In ISO14229-1, except bit3:

Except for ConfirmedDTC, there are no other mandatory constraints.

First, let’s understand a few concepts: test, operation cycle, and aging.

Testing refers to the process of using online diagnostic software algorithms to determine the fault status of a component or system within an operating cycle. In an operating cycle, the test may be run only once, or it may be run periodically.

The operation cycle defines the start and end conditions of the test. The body and chassis domains are generally determined by the OEM or supplier themselves (such as power on and off, sleep and wake-up, etc.), and there are other standard regulations for the power domain.

Aging: If the fault of a recorded DTC no longer occurs, it will not be recorded. At this time, a process is required: when the test result shows a certain number of times of Passed in a row, the DTC can be cleared. This process is called aging. The number of times is called the aging threshold.