Calibration Package (CALPAC)
Some models use a PROM and a CALPAC. CALPAC provides fuel delivery back-up so engine runs in case of PROM or ECM failure. Any time ECM is replaced, PROM and CALPAC must both be installed into replacement ECM. If battery voltage is removed, CALPAC information is retained.
Memory Calibration (MEM-CAL)
Some vehicles may use a ECM containing a MEM-CAL unit. This assembly contains functions of PROM and CALPAC. If power to ECM is removed, MEM-CAL information is retained. MEM-CAL also contains an internal ESC module on models equipped with ESC.
Note. Components are grouped into 2 categories. The first category is INPUT DEVICES, consisting of components which control or produce voltage signals monitored by the control unit. The second category is OUTPUT SIGNALS, consisting of components controlled by the control unit.