August 23, 2020
6
Connect the Transmission
1. Connect the Main Transmission Plug
For easy identification, all connectors are labeled.
Safely route the harness AWAY FROM the exhaust system, the rotating drive shaft, or other
moving parts of the drivetrain.
Connect the main transmission plug to the corresponding plug on the transmission.
2. Connect the Transmission Output Speed Sensor (TOSS)
Choose the correct TOSS adapter for your transmission and connect it to your vehicle’s sensor.
3. Connect the Transmission Input Speed Sensor (TISS)
If your transmission has a TISS, connect the mating plug on the harness. Note that some GM
harnesses fit multiple transmissions, so your loom may have a TISS plug even though your
transmission does not have a TISS sensor. In this case, tie the unconnected plug safely out of the
way with a cable tie; do not connect it.
3. Connect the Lever Position Sensor
Some transmissions, including Ford and Nissan, require an additional lever sensor connector.
Connect this sensor to the supplied plug on the harness.
4. Connect the Reproduced TOSS Signal
Use the purple/white wire labeled “SPEEDO OUT” to connect to your vehicle’s speedometer or
engine ECM.
DO NOT connect to your original TOSS wires.
On GM vehicles,
you can patch this connection to the cable that originally connected to the TOSS.
GM does not make a plug and cable to fit, so you must patch the wire directly.
4WD Only: Connect the Transfer Case Low Range Calculation Wire
On four-wheel-drive vehicles, connect the transfer case low range switch to the yellow
Transmission Wiring Harness wire labeled “TRANSFER CASE.” During setup, you will enter the
transfer case ratio into the COMPUSHIFT app so it will operate correctly in the LOW Range.
