• These appear when an irregularity detected in a monitored system. The code for a failed system is stored in the PCM memory in the first drive cycle. This code is called the pending code. If the PCM determines that the system returned to normal or the problem was mistakenly detected, the PCM deletes the pending code. If the problem is found in a second drive cycle also, the PCM determines that the system has failed, and the DTC is stored.