Unprogrammed control module for GM 6T40 and 6T45 automatics, replacing 24260820 on Cruze, Regal and Terrain with U0101 or shift faults.
When a Chevrolet Cruze, Buick Regal or GMC Terrain with the GM 6T40 or 6T45 six-speed starts throwing U0101 (lost communication with the TCM), stacks up solenoid performance codes, or drops into a fixed-gear limp mode, the part most shops end up replacing is the transmission control module assembly. This listing replaces GM part number 24260820. As the photos show, it is the complete assembly: the aluminum-cased electronic module mounted on the black solenoid body, with all seven solenoids installed. It is new aftermarket, it ships unprogrammed, and it must be programmed to the vehicle before the transmission will work.
GM calls this assembly the TEHCM, short for transmission electro-hydraulic control module. On the 6T40 family the computer and the solenoids are one unit that lives inside the transmission, bolted to the valve body behind the control valve body cover, rather than a separate box under the hood. The input and output speed sensors and the internal mode switch are wired straight into it, which is why GEARS notes there is very little you can test from outside the case: you confirm power, ground, the park/neutral and brake signals, and serial data, and everything else is read on a scan tool.
The solenoid body carries six pressure control solenoids and one on/off shift solenoid. Line pressure, the 3-5-R, R-1/4-5-6, 2-6 and 1-2-3-4 clutch regulators, and converter clutch apply are all metered here. Because the 6T40 shifts clutch-to-clutch, any electrical or valve fault in this assembly shows up immediately as a shift quality complaint.
Start with codes in every module, not just the transmission, and check for calibration updates; GM corrected a harsh 2-3 on some 2011 Equinox and Terrain 2.4L models with new TCM software alone. Run the solenoid cleaning procedure on a capable scan tool. If a solenoid code survives that, the assembly can be bench tested on air with the solenoids cycled. A solenoid performance code can also be a leaking clutch circuit, so do not condemn the module on one code. Our 6T40 shift solenoid guide walks through the resistance specs and air checks, and 6T40 common problems and fixes covers the mechanical failures that mimic an electrical one.
The listing covers Chevrolet Cruze, Buick Regal and GMC Terrain with the 6T40 or 6T45 that use GM 24260820. GM built two generations of this unit and they are not interchangeable. Read the eighth digit on your existing assembly: 1, 2 or 3 is Generation 1 (with pressure switches), B, C or D is Generation 2 (no pressure switches). Match that and the part number on your old module to 24260820, or send us your year and VIN and we will check it. Other 6T40 service parts, such as the 6T40 solenoid kit for owners who only need individual solenoids, are listed separately.
| Replaces GM Part Number | |
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| Mounting | |
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| Programming | |
| Listed Fitment |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is the internal assembly. On the 6T40 and 6T45 the control module and solenoid body are one unit that bolts to the valve body inside the transmission, behind the side cover. The photos show the module on the solenoid body with all seven solenoids fitted.
No. It ships unprogrammed. A dealer or a shop with GM programming software has to set it up for your VIN before the transmission will shift, and an adaptive values learn should follow.
No. GM changed the PCS2 and PCS5 solenoid locations and operation and dropped the pressure switches for Generation 2. Check the eighth digit on your old module (1-3 is Gen 1, B-D is Gen 2) and match it, along with part number 24260820.
Dexron VI. Check the level at the case check plug with the engine running and the fluid at 85-95 C. These units overfill easily and will vent fluid if overfilled.
Yes. U0101 means other modules lost communication with the transmission control module. Verify power, ground and the serial data circuits at the case connector first, because a wiring fault sets the same code.
