TM-9-2320-387-24 HMMWV Direct Support & General Support Maintenance Manual Volume 1 Download
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REFERENCE INFORMATION TRANSMISSION SYSTEM DTC 73 Pressure Control Solenoid (PCS) Circuit Current Error (Force Motor Circuit) Circuit Description: The Pressure Control Solenoid (PCS) is a TCM- controlled device used to regulate transmission line pressure. The TCM compares TP voltage, engine rpm, and other inputs to determine the appropriate line pressure of a given load. The TCM will regulate the pressure by applying a varying amperage to the PCS. The applied amperage can vary from 0.1 to 1.1 amp. The TCM then monitors the amperage at the return line. DTC 73 Will Set When: l The return amperage varies greater than 0.16 amp from the commanded amperage. l All conditions are met for 1 second. DTC 74 Transmission Input Speed Sensor (TISS) Circuit Circuit Description: The Transmission Input Speed Sensor (TISS) consists of a permanent magnet surrounded by a coil of wire. As the forward clutch housing rotates, an AC voltage is induced in the circuit. The signal voltage and frequency vary directly with the forward clutch rotational speed. DTC 74 WZL Set When: l Transmission range is not in park or neutral. l Engine speed is greater than 300 r-pm. TM 9-2320-387-24-1 DTC 75 System Voltage Low Circuit Des&p tiorx Ignition voltage is supplied to the control module to indicate the status of the ignition switch Battery voltage is supplied to the control module to, in part, maintain memory of learned functions and parameters. DTC 75 Will Set When: l The ignition is ON. l Ignition feed voltage to the control module is less than the graduated scale of: - -40°F (-40°C) = 7.3 volts. - 194°F (-90°C) = 10.3 volts. - 302°F (-150°C) = 11.7 volts. l Engine speed is greater than 1,000 r-pm. l All conditions are met for 4 seconds. DTC 79 Transmission Fluid Overtemp Circuit Description: The Transmission Fluid Temperature (TFT) sensor is a thermistor that controls the signal voltage to the TCM. The TCM supplies a &volt reference signal to the sensor on Circuit 923A. When the transmission fluid is cold, the sensor resistance is high and the TCM will sense high signal voltage. As the transmission fluid temperature warms to normal transmission operating temperature 212°F (lOO”C), the sensor resistance becomes less and the voltage decreases to approximately 1.5 to 2.0 volts. l Transmission output speed is greater than 200 rpm. l Transmission input speed less than 50 rpm. l AI1 conditions are met for 2 seconds. DTC 79 Will Set When: l Transmission fluid temperature is greater than 295°F (146°C). l All conditions are met for 30 minutes. 2-399