TM-9-2320-280-20 HMMWV Technical Manual Unit Maintenance Volume 1 Download
Page 528 of 890
TM 9-2320-280-20-1 TRANSMISSION SYSTEM (4L80-E) REFERENCE INFORMATION DTC 59 Transmission Fluid Temperature (TFT) Sensor Circuit High (Low Temperature Indicated) Circuit Description: The TFT sensor is a thermistor that controls the signal voltage to the TCM. The TCM supplies a 5-volt reference signal to the sensor on TWC Pin “L.” 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 (100°C), the sensor resistance becomes less and the voltage decreases to approximately 1.5 to 2.0 volts. DTC 59 Will Set When: . Signal voltage indicates TFT less than -34°F (-37°C). ● Condition is met for 1 second. DTC 68 Transmission Component Slipping Circuit Description: The TCM monitors the difference in engine Speed and input Speed. DTC 68 Will Set When: ● TCC slip speed greater than 200 RPM. ● Fourth gear is indicated. ● TCC is locked. ● Not in park/neutral. ● All conditions are met for 2 seconds. DTC 69 Torque Converter Clutch (TCC) Stuck “ON” Circuit Description: The TCM commands the TCC PWM solenoid “ON” by modulating TCC signal fluid acting on the converter clutch shift vaIve. Then TCC fluid applies the torque converter clutch. DTC 69 Will Set When: ● TCC slip speed RPM indicates between -5 and +10 RPM. . TCC solenoid is commanded “OFF.” ● TP sensor signal is greater than 25%. DTC 71 Engine Speed, Sensor Circuit Low Circuit Description: The camshaft position sensor (CPS) detects the rotational speed of the camshaft. As the camshaft rotates, an AC signal is generated in the circuit. This signal provides the input to determine engine speed for use in various calculations including TCC slip speed and overdrive ratio. DTC 71 Will Set When: ● Engine speed less than 50 rpm ● Transmission range indicates, R, D4, D3, or D1. ● Conditions are met for 2 seconds. ● Trans range switch indicates D3 or D4. ● Commanded gear indicates 2nd or 3rd gear. ● All conditions are met for 2 seconds. 2-424