Principles of operation: ZF 4HP20 automatic gearbox
XANTIA II · Repair procedures · HP20 (AG) AND BVA4 SINCE RPO 7668 · Data - identification · Reference B2CB21P0
1. General : Gear selection law The gearbox operating point is defined by the following information : Throttle butterfly position Vehicle engine load and speed In operation, the decision to change gears is taken by the ECU using a set of graphs known as the "selection laws" Each change pattern…