What is ETS enhanced Traction system and what does it do?

Traction control systems, on current production vehicles, are typically (but not necessarily) electro-hydraulic systems designed to prevent loss of traction (and therefore the control of the vehicle) when excessive throttle or steering is applied by the driver. Although similar to the Electronic Stability Control systems, the Traction Control systems do not have the same goal as them. The intervention can consist of any, or all, of the following: Retard or suppress the spark to one or more cylinders Reduce fuel supply to one or more cylinders Brake one or more wheels Close the throttle, if the vehicle is fitted with drive by wire throttle. The brake actuator, and the wheel speed sensors, are the same as that used for anti-lock braking systems. Additional information : The Enhanced Traction System is an all-speed engine based traction control system used by General Motors Corporation in many of their models. "From the Service Manual: Enhanced Traction System (ETS) The Enhanced Traction System (ETS) is designed to limit wheel slip during acceleration. This objective is accomplished by cutting fuel to selected cylinders, retarding spark and upshifting the transmission. The EBCM monitors wheel speed slip through the ABS wheel speed sensors and determines the desired torque reduction needed to minimize wheel spin. The torque reduction the EBCM requests may result in a combination of fuel cutoff, spark retard, and upshifting the transmission, depending on the torque reduction required. This request is sent from the EBCM through the serial data link to the Powertrain Control Module (PCM). The PCM then calculates and employs fuel cutoff and spark retard values to achieve the requested engine torque. If the EBCM determines that the engine torque reduction is not sufficient to minimize wheel spin, it will request a transmission upshift. The ETS will be enabled when the ETS switch is in the ON position (TRAC OFF indicator not illuminated), the engine coolant temperature is within normal operating range and the manifold air temperature is within normal operating range. There are a number of reasons that the ETS will be inhibited or disabled. * INHIBITED: Not all modes of ETS are available. i.e.: no spark retard, but transmission upshifts are still available. * DISABLED: No ETS modes are available Some of the items that can inhibit or disable ETS are: * ETS OFF switch is in the OFF position. (Disabled) * EBCM senses a valid brake switch input. (Disabled) * Park brake is engaged. (Disabled) * Catalytic converter temperature rises above the normal operating range. (Inhibited) * Engine coolant temperature is not within normal operating range. (Inhibited) * Manifold air temperature is not within normal operating range. (Inhibited) * PCM sets a DTC that turns on the CHECK ENGINE lamp. (Inhibited or Disabled) * PCM sets a Failure Record that does NOT turn on the CHECK ENGINE lamp. (Inhibited or Disabled) * EBCM sets a DTC C1221, C1222, C1223, C1224, C1225, C1226, C1227, C1228, C1232, C1233, C1234, and/or C1235 (any wheel speed sensor DTC). (Disabled) Refer to Self-Diagnostics for more information. ETS OFF Switch The ETS OFF switch is a momentary contact switch. The ETS OFF switch enables or disables the enhanced traction system. When the EBCM needs to illuminate the TRAC OFF or LO TRAC indicators, it will transmit a signal (via serial data link) to the Electronic Instrument Panel Cluster (IPC) and the IPC will illuminate the indicator. The amber TRAC OFF indicator will be illuminated when ETS is disabled or when the driver switches ETS off with the ETS OFF switch. As a bulb check procedure, the EBCM will command the ETS indicator ON for 3 seconds when the EBCM receives power (ignition in ON position). With the ignition in the OFF or START positions (loss of serial data), the IPC will illuminate the ETS OFF indicator lamp. The amber LO TRAC indicator will be illuminated to alert the driver of a low traction situation and to inform the driver the ETS is operating. As a bulb check procedure, the EBCM will command the LO TRAC indicator ON for 3 seconds when the EBCM receives power (ignition in ON or START positions). With the ignition in the OFF position (loss of serial data), the IPC will illuminate the LO TRAC indicator. " I found the above information in http://www.gaownersclub.com/forum/showthread.php?s=0e40c3fe48fba12fdcf38f4fbbf2a878&threadid=92&goto=nextoldest