PANEL-OUTER 2526971 - Caterpillar

Industrial Engine:
C4.4 (S/N: 4447083-7083,7086-7088,7104-7107,7118-7118,7182-7182,7198-7199,7262-7264,7282-7282,7290-7291,7317-7317,7326-7329,7331-7333)
C6.6 (S/N: 66612253-12253,12256-12257,12260-12261,12289-12289,12317-12319,12344-12349,12351-12353,12356-12356,12358-12360,12363-12367,12376-12387,12389-12390,12392-12392,12394-12395,12404-12404,12406-12409,12413-12431,12433-12433,12444-12446,12448-12449)
Description of Change: There have been a number of isolated instances of issues with the Electronic Control Module (ECM) on applications with a power supply of 24 Volts. The issues with the ECM have occurred if the keyswitch is turned to the RUN position or the OFF position.The issues are caused by the high Gate to Source voltage threshold of the Field Effect Transistor (FET) that is installed in the ECM. The high Gate to Source voltage of the FET affects the timing of the FET when the FET stops the supply to the boost power. The supply to the boost power is turned off when the engine is started or when the engine is stopped. The power supply during engine operation is not affected.A new FET has replaced the existing FET. The new FET has a lower Gate to Source voltage threshold.Adaptable To: The part numbers of the 331-7539 Electronic Control Module and 331-7540 Electronic Control Module have not changed.For the correct procedure to replace an ECM, refer to Disassembly and Assembly, "Electronic Control Module - Remove and Install".