Description and identification of fault codes

Fault codes are divided into current fault codes and historical fault codes.

The current fault code, also known as hard fault code, is the fault code generated by the ongoing fault; Is the current fault that does exist, and the fault code also exists. It belongs to the current fault code generated by the continuous fault, and it will not be cleaned up.

Historical fault code is also known as intermittent fault code or soft fault code, which is the fault code that has not been cleared by the current failure occurred in the past. There are two types of historical fault codes. One is that the fault has been eliminated but the fault code has not been cleared, and the fault code will not be generated again after it can be cleared. The other is that the fault has not been eliminated, but is not currently occurring, so the fault code can only be completely cleared after the fault is completely eliminated.

The current fault code is the actual fault, which is easy to judge. Therefore, the current fault code is generally solved first, and the historical fault code is temporarily used as a reference for fault diagnosis.

Historical fault codes and current fault codes can be distinguished by the following methods:

1. Firstly, read all fault codes with a diagnostic instrument;

2. Clear all fault codes;

3. Test run. It is emphasized here that the test run is not to start the engine in situ, but to carry out road test.

4. Read the fault code again. The fault code read out the second time is the current fault code, which is read at the first time, and the fault code not read at the second time is the historical fault code.