Circuit/System Description

WARNING: This page is about a different car, the 2011 GMC Yukon, 2011 Chevrolet Tahoe, and 2011 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.

The output speed sensor assembly has 2 internal hall-effect type sensors, and is capable of sensing both speed and direction. The output speed sensor mounts to the A/T rear case assembly and is connected to the control solenoid valve assembly through a wire harness and connector. The sensor faces the hybrid direct, 2-3-4 clutch housing assembly machined teeth surface. The sensor receives 8.3-9.3 volts on the OSS supply voltage circuit from the transmission control module. As the output shaft rotates, the sensor produces a signal frequency based on the machined surface of the output shaft.

The two sensor elements in the output speed sensor assembly are spaced approximately 1/2 a tooth apart.

When the vehicle is moving in a forward direction, sensor A detects a particular tooth before sensor B.
When the vehicle is moving in a reverse direction, sensor B detects a particular tooth before sensor A.

The electronics in the sensor combine the two signals and send a signal with a different pulse width. This signal is interpreted by the transmission control module for speed and direction and is transmitted through the serial data circuits to the engine control module (ECM) and the hybrid powertrain control module. The ECM, hybrid powertrain control module, and transmission control module compare the OSS signal with the anti lock brake system wheel speed sensor signal. The hybrid powertrain control module also compares the output shaft direction with the drive motor 1 and drive motor 2 direction.