Continuous Memory Self-Test

Continuous memory DTCs are set when a continuous memory self-test is performed. Continuous memory self-test is a functional test of PCM performed under any condition (engine running or off) with ignition on. Unlike KOEO and KOER self-tests which can only be activated on demand, continuous memory self-test is always active in monitoring the system. When a fault is detected, DTC will be stored in memory. This makes it possible to diagnose intermittent faults.

There are 2 types of continuous memory DTCs. First type is emission-related and will illuminate the Malfunction Indicator Light (MIL) located in instrument cluster. The second is a non-emission related and will never illuminate MIL.

For emission-related MIL codes, Powertrain Control Module (PCM) will store DTC in continuous memory when a fault is detected for the first time. At this point, DTC will not illuminate MIL and is considered a pending code. If same fault is detected after next ignition start-run cycle, emission-related code will illuminate the MIL. The MIL will remain on even if fault is intermittent. The MIL will be turned off if fault is not present through 3 consecutive drive cycles, or if PCM reset is performed. Also, an emission-related pending code and non-emission related codes will be erased after about 40-80 vehicle warm up cycles or PCM reset.