Detailed description of DTC status definition

Detailed description of the definition of each bit of DTC status:

1.0 DTC status bit0: testFailed

If the most recent test result is Failed, the status bit 0 of the corresponding DTC is set to 1. When the reset condition defined by the OEM is met, or the most recent test result is Passed, or the DTC clearing command is executed using the diagnostic equipment, the status bit 0 of the corresponding DTC is reset to 0. The switching logic is as follows. The initial value of this bit is 0.

source: ISO14229-1

1.1 DTC status bit1: testFailedThisOpera ti onCycle

For the current operation cycle, whether a test result of Failed occurs once, if it does, the corresponding DTC status bit 1 is set to 1. The initial value of this bit is 0. If it is set to 1, then only when the operation cycle is changed or the DTC clearing instruction is executed using the diagnostic equipment, this bit can be reset to 0, as shown below:

source: ISO14229-1

1.2 DTC status bit 2: pending gDT C

Whether a test result of Failed occurs in the last or current operation cycle, if so, the corresponding DTC status bit 2 is set to 1. The initial value of this bit is 0. If it is set to 1, the bit can only be reset to 0 when the test is completed and no Failed occurs when the current operation cycle is completed, or the DTC clearing instruction is executed using the diagnostic equipment, as shown below:

source: ISO14229-1

1.3 DTC status bit 3: confirmedDTC

When the number of detected faults is sufficient, the corresponding DTC needs to be stored in non-volatile memory. If the DTC has been stored in non-volatile memory, the status bit 3 of the DTC is set to 1, but this bit being 1 does not mean that the fault still exists. If the test result is Passed, it means that the fault represented by this DTC has disappeared. How to reset to 0, use the diagnostic equipment to execute the clear DTC command or reach the aging threshold, etc., as shown below:

source: ISO14229-1

1.4 DTC status bit 4: testNotCompletedSinceLastClear

Since the last fault information was cleared, has a DTC test been performed (regardless of the test result, only whether it was tested). If it was performed, the status bit 4 of the DTC is set to 0. If it is set to 0, the bit can be reset to 1 only after the diagnostic equipment executes the clear DTC command, as shown below:

source: ISO14229-1

1.5 DTC status bit 5: testFailedSinceLastClear

Since the last fault information was cleared, has a DTC test result of Failed appeared? If so, the DTC status bit 5 is set to 1; if it is set to 1, then this bit can only be reset to 0 when the operating cycle changes and meets the aging threshold condition, or the clear DTC command is executed using the diagnostic equipment, etc., as shown below:

source: ISO14229-1

1.6 DTC status bit 6: testNotCompletedThisOperationCycle

In the current operation cycle, whether a test of a certain DTC is executed (regardless of the test result, only whether it is tested). If it is executed, the status bit bit6 of the DTC is set to 0; if it is set to 0, the bit can be reset to 1 only after the diagnostic equipment executes the clear DTC instruction or the current operation cycle is completed, as shown below:

source: ISO14229-1

1.7 DTC status bit 7: warningIndicatorRequested

Some special DTCs are associated with user-visible warning indicators, such as warning lights on the instrument panel, or text messages. The status bit 7 of this DTC is used for this type of DTC. Setting it to 1 indicates that the server requests to activate the warning indicator, and setting it to 0 indicates that the server does not request to activate the warning indicator. The specific setting conditions are as follows:

source: ISO14229-1

Note that if this DTC does not support warning indication, this bit is always set to 0.