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4L80E error code 73 - trans light always on

RF5

New member
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Location
Brazil
Hi there.
My 1988 Humvee M1097A2 (rebuilt by Army on 2013) with a 4L80E transmission and a 6.5L NA has the trans light always on as soon as the ignition is turned on and goes out after the ignition is turned off only.
I followed the DVOM procedures to check the error code 73 and realized that the pressure solenoid was with the resistance out of range (6.7 ohms). I replace de solenoid and also the internal harness, as the trans conector was full of oil. The oil is at the correct level as well.
The truck runs great and all the gears shifts perfectly, even before the PCS and internal harness replacement.
Anyone had this issue? Any idea how to solve this?
Thanks!
 

REF

Active member
Steel Soldiers Supporter
126
134
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Location
Porterville Calif
My guess,
Check to make sure the engine RPM senor in the timing cover is hooked up so the TCM knows that the engine has started and to turn out the light. Without engine RPM the torque converter lock up will not work but you will have all 4 gears it will just feel sluggish. The original plug in the harness for rpm should be a 2 pin connector under the dog house on the drivers side sticking out of the main harness about the same level as the oil pressure sender on the engine. The sensor will be in the front timing cover on the drivers side just above the oil pan. I have seen times when they do a swap they don't bother to extend the wires in the harness to reach the new position of the RPM sensor.

Just takes a quick look, my best guess from this description.

Edit: Just saw you don't have a turbo engine, so the connector should be sticking out of the main harness about the same level as your heater temp controls.
 
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