TM 10-3930-675-10 0020 00-24 ERROR CODES - CONTINUED 0020 00 Table 4. Error Codes - Continued. ERROR CODE DISPLAY LAYOUT DRIVER ACTION ERROR CODE EXPLANATION VEHICLE LIMITATIONS 638 Finish Mission Notify maintenance. Information/Maintenance Short circuit to ground at trans- mission sump temperature sensor input - voltage too low Cables defective. Sensor defective. Connector pin broken. None 639 Finish Mission Notify maintenance. Information/Maintenance Short circuit to battery voltage or   open   circuit   at   converter output temperature sensor input - voltage too high Cables defective. Sensor defective. Connector pin broken. None 640 Finish Mission Notify maintenance. Information/Maintenance Short circuit to battery voltage or   open   circuit   at   converter output temperature sensor input - voltage too low Cables defective. Sensor defective. Connector pin broken. None 649 Finish Mission Notify maintenance. Information/Maintenance Short circuit to battery voltage or open circuit at engine speed input - transmission ECU mea- sures   a   voltage   higher   than 7.0V at speed input pin Cables defective. Sensor defective. Connector pin broken. Gearshift quality is reduced due to another control mode. (Operating mode: substitute clutch control) 650 Finish Mission Notify maintenance. Information/Maintenance Short    circuit    to    ground    at engine speed input - transmis- sion  ECU  measures  a  voltage less  than 0.45V at  speed input pin Cables defective. Sensor defective. Gearshift quality is reduced due to another control mode. (Operating mode: substitute clutch control)