mean the change in the pot's voltage is not a perfect straight line from the pot's lowest setting to the highest. (Fig. 10) The module then learns whatever SAS value it sees and sets that value as "0 Degrees Straight Ahead." Other SAS require only turning the steering wheel from lock to lock. SAS in some vehicles may require a scan tool operation. Neglecting to perform this procedure can result in a DTC in the ABS / Stability control module, a steering wheel that is not straight when driving straight or (worst case scenario) a steering wheel that fights you while driving down the road. Power Windows / Power Sunroofs Dave Hobbs Windows and Sunroofs with express auto open or close functions may sometimes require a relearn procedure after a 12-volt battery power reset has occurred. Reset procedures vary from OEM to OEM. Here is a sample procedure for a mid 2000's Toyota 4-Runner 's power windows and sunroof: Figure 10: This chart shows one reason HVAC actuators containing position sensors (almost always potentiometers) require a relearn procedure when replaced, when the battery power has been removed, or whenever the HVAC control module has been replaced / reprogrammed. Common (affordable) manufacturing tolerances in the voltage output of the potentiometer mean a non linear output. To learn the degree of non-linearity of the sensor, a full sweep is performed on the actuator by the HVAC control module To reset the moonroof one-touch operation: With ignition switch in the "ON" position, do the following: 1. Push and hold the "TILT UP" side of the switch until the moon roof tilts all the way up and then tilts down slightly (approximately 10 mm [0.39 in.] at the rear). 2. Check for proper operation of the "one- touch slide open/close" and "one-touch tilt up/down" functions by pushing the switch briefly to the "SLIDE OPEN" and "TILT UP" positions. Steering Angle Sensors Steering Angle Sensors (a.k.a. SAS) fall into designs that are either digital or analog. These sensors are extremely important inputs on vehicles that use: a. Stability Controls b. Electric Power Steering c. Land Departure Avoidance d. ADAS - Automated Driver Assistance System (Semi-Autonomous Driving) A Battery Cable Removal TECH TIP to Remember: After the ignition switch is turned off, some OEM radios record various types of memory and settings. In case your customer 's vehicle is one of those applications, after turning the ignition switch off, make sure to wait at least 90 seconds before disconnecting the battery cable from the negative battery post. ■ The correct method for relearning / resetting a vehicle's SAS varies by OEM. Some vehicles that utilize high resolution active WSS (Wheel Speed Sensors) require only driving the vehicle in a straight line for a short distance. As each WSS reads the exact MPH for a given distance, the ABS module assumes the vehicle is being driven straight. September 2017 To reset the driver's side power window autoclose: 1. Push down and hold the driver's door power window switch to completely open the window. 2. Pull and hold up the driver's door power window switch until the window closes. Continue holding the switch for approximately one second until the switch changes from blinking to a constant illumination. 3. Check for proper operation of the "one- touch open/close" by pushing the switch briefly to the "DOWN" and "UP" positions. 5 MACS Service Reports