TM-9-2320-280-20 HMMWV Technical Manual Unit Maintenance Volume 1 Download
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TM 9-2320-280-20-1 REFERENCE INFORMATION TRANSMISSION SYSTEM (4L80-E) DTC 85 Undefined Ratio Error Circuit Description: The control module calculates ratio based on the transmission input speed and output speed sensor reading. The control module compares the known transmission ratio to the calculated ratio for the particular gear range selected. DTC 85 Will Set When: ● TP is greater than 25%. . Not in park neutral, or 4th gear. . Engine speed is greater than 300 rpm. ● Vehicle speed is greater than 7 mph (11 kph). ● All conditions are met for 2 seconds. DTC 86 Low Ratio Error Circuit Description: The control module calculates ratio based on the transmission input speed and output speed sensor readings. The control module compares the known transmission ratio to the calculated ratio for the particular gear range selected. DTC 86 Will Set When: ● ● ● ● ● ● Not in park, reverse, or neutral. Engine speed greater than 300 rpm. TP greater than 25%. Vehicle speed is greater than 7 mph (11 kph). Trans gear ratio is less than 1.06 in first or second gear. All conditions are met for 2 seconds. DTC 87 High Ratio Error Circuit Description: The control module calculates ratio based on the transmission input speed and output speed sensor readings. The control module compares the known transmission ratio to the calculated ratio for the particular gear range selected. DTC 87 Will Set When: ● TP greater than 25%. ● Not in park, reverse, or neutral. . Engine speed greater than 300 rpm. . Vehicle speed greater than 7 mph (11 kph). ● Transmission temperature is greater than 68°F (20°C). ● All conditions are met for 2 seconds. 2-427