Description & Operation: Introduction

NOTE: New for 2002, the Powertrain Control Module and Transmission Control Module have been combined into a single control module. This new module is referred to as the Next Generation Controller (NGC) and will be referred to as the Powertrain Control Module (PCM). New diagnostic procedures and new DTC numbers are 2 of the changes which reflect the new combined module technology. The PCM has 4 color coded connectors (Cl-Black, C2-Gray, C3-White and C4-Green). Each PCM connector has 38 terminals. New equipment was introduced to help diagnose and repair at the PCM terminals and harness connectors. The Miller Terminal Removal Pick (3638) must be used to release the connectors, or harness and connector damage will occur. Also, the Miller Special Tool (8815 Pinout Box) is used instead of probing the PCM terminals. Harness and connector damage will occur if pinout box is not used.

The 42LE is an electronically controlled 4-speed transaxle. Transaxle uses hydraulically operated clutches controlled by Powertrain Control Module (PCM). Transaxle consists of 3 multiple-disc input clutches, 2 multiple-disc holding clutches, 4 hydraulic accumulators and 2 planetary gear sets to provide 4 forward speeds and reverse. See Figure.

PCM receives information from various sensors and controls the solenoid assembly through the transmission control relay. Solenoid assembly consists of 4 solenoids for controlling hydraulic pressure to 4 of the 5 transaxle clutches.

PCM contains an adaptive memory which learns application and release rates of transaxle components for smooth operation. PCM also learns rate at which applied elements build pressure sufficient for a speed change. Adaptive control can adapt to altitude, temperature, engine output, etc.