Bench Testing the 6L50-6L80-6L90-6T70-6T75 TEHCM


Bench Testing the 6L50-6L80-6L90-


6T70-6T75 TEHCM


by Steve Garrett members.atra.com www.atra.com


Figure 1 I 14


n past articles, I’ve spent a lot of time covering the operation of GM’s solenoid body/con-


troller, better known as a TEHCM (Transmission Electrical Hydraulic Control Module) The TEHCM houses the TCM,


shift solenoids, PWM solenoids, pres- sure switches, and temperature sensors for the transmission or transaxle. It’s mounted inside the unit, attached to the valve body. The TEHCM commu- nicates with the components outside the transmission or transaxle via the


data bus. Testing the components requires


some special tools, including: • Scan tool • DT47825-100 solenoid test plate • Appropriate vehicle interface harness DT47825-20 (6T70- 6T75) or DT47825-10 (6L50- 6L80-6L90)


• DVOM • Signal generator, such as Kent Moore J-38522 (EL38522)


Many technicians inquire regard- ing the procedure to bench test the


TEHCM. GM developed a test plate to allow you to conduct static tests of the solenoids. A static test will help you find a solenoid that’s stuck open or closed, but it won’t show you whether solenoid flow rate is correct at various commanded positions. You can use the test plate anytime


you have the TEHCM removed from the vehicle, such as during a rebuild. You’ll need the vehicle to complete this test, because the scan tool still relies on the vehicle data bus for communication with the TEHCM.


GEARS August 2012


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