The multicube or the electronic control module according to the make and model of the car is located on the front passenger side at the back of the instrument panel. Depending on the specific car models that the ECM is designed for, the calibrated or built-in PROM contains specific information about the car's weight, make and model of the engine, transmission type and axle ration. Original equipment numbers should be confirmed in order to prevent the installation of a non-related PROM because units referred to as controllers, replacements for the ECM, do not include a PROM. It will be important that the PROM from the old ECM that is being married to the new unit is delicately removed and then put in place. Also, on the same access cover as the PROM but in the form of a calpak which can deliver fuel if there are issues with other ECM parts. In the case of a faulty ECM, the PROM should be checked for correctness as trouble code 51 mean incorrect installation. If the ECM is being replaced, it is mandatory to manually enter the broadcast code and the production ECM number on a new part label put on the new ECM, but nothing to be recorded on the cover of the ECM. Before the ECM can be removed, the battery must be disconnected, the wiring harness and mounting brackets and screws must be disconnected as well as removed before pulling the ECM out of the passengers compartment. The PROM and calpak are located under the access cover that is located on the top of the control unit. Rocker type PROM removal tool should be inserted by engaging one end of the PROM carrier with the tool and pressing on the vertical bar and then rocked upwards by the engaged end of the PROM carrier. Same operations are to be performed at the other end till the PROM carrier and PROM are out of the socket and a removal tool is used to avoid damage on the PROM or socket.