SL L4-1.9L SOHC VIN 9 (1991)
Engine Control Module: Description and Operation
Powertrain Control Module (PCM)
PCM Location - Under Left Hand Dash.
DESCRIPTION
The Powertrain Control Module (PCM) uses signals from various sensors in order to optimize the control of the engine, transaxle, and electrical
variable orifice power steering system. The subsystem also provides information to other subsystems and to service equipment.
The PCM is a microprocessor based computer that is the main component of the powertrain control system.
There are four different versions of the PCM:
1. Throttle body injection with manual transaxle.
2. Throttle body injection with automatic transaxle.
3. Multi-port fuel injection with manual transaxle.
4. Multi-port fuel injection with automatic transaxle.
Each powertrain control module (PCM) contains either one or two separate controllers located in one assembly. Manual transaxle versions contain
only the Engine Controller (EC). The automatic transaxle versions contain an Engine Controller (EC) and a Transaxle Controller (TC). The
physical size of the PCM will be the same, regardless of the number of controllers it contains.
PCM EEPROM
The PCM EEPROM stores vehicle information such as engine and transaxle calibrations. Vehicle Identification Number, programmable vehicle
option content and Malf history.
