For 1990-2009 cars

DTC | DTC Parameters | Diagnosis
--- | --- | ---
DTC P0601 PCM Memory | This DTC will set when the PCM determines that the ECM RAM memory is faulty. | Record all PCM DTCs and include with repair information. Replace and reprogram the PCM.
DTC P0602 PCM Not Programmed | This DTC will set if the PCM is not programmed correctly. | Record all PCM DTCs and include with repair information. Reprogram the PCM. If this fault returns, replace and reprogram the PCM.

DTC P0601 diagnostic is checked continuously.

DTC P0602 diagnostic is checked only once as soon as the ignition is turned ON.

DTC P0601 and P0602 are type A DTCs.