P0601 BMW - ECM Self Check Fault
- Engine control Module(ECM) harness is open or shorted
- Engine control Module (ECM) cicuit poor electricl connection
- Low battery voltage
The nerve center of the fuel injection system is the engine control module (ECM). The ECM constantly supervises the information from various sensors, and regulates the systems that start after vehicle performance. The ECM is also empowered to control all the diagnostic functions of the system. It can detect operational flaws and caution the driver through the Malfunction Indicator Lamp (MIL) It also records and stores a Diagnostic Trouble Code (DTC) which detects the likely problem- making parts to help the technician while repairing.
In order to house the program information and the calibrations required for engine, trans-axle diagnostics operation an electrically erasable programmable read only memory (EEPROM) is used. For detecting errors in the software the ECM uses a specially devised value known as the checksum.
The checksum (self explanatory) is a value that is the sum total of all the numbers in the software added together. If the values recorded by the ECM and the checksum do not match then a checksum error is highlighted.