Powertrain Control Module (Pcm)
| ITEM | DESCRIPTION |
|---|---|
| 1 | Powertrain Control Module (PCM) |
| 2 | Mounting bracket |
The Powertrain Control Module (PCM) is located on the left side rear corner of the engine compartment on Left Hand Drive (LHD) vehicles and on the right side rear corner of the engine compartment on Right Hand Drive (RHD) vehicles.
The PCM receives inputs from various sensors and outputs reference voltages and signal information to other sensors for engine control.
Inputs:
- Crankshaft Position (CKP) sensor
- Camshaft Position (CMP) sensor
- Ambient Air Temperature (AAT) sensor
- Mass Air Flow and Temperature (MAFT) sensor
- Manifold Absolute Pressure and Temperature (MAPT) sensor
- Accelerator Pedal Position (APP) sensor
- Brake pedal switch
- Electric throttle
- Engine Coolant Temperature (ECT) sensor - electric thermostat housing
- Engine Coolant Temperature (ECT) sensor - Radiator outlet
- Engine cooling fan control module
- Variable coolant pump - shroud position
- Heated Oxygen Sensor (HO2S)
- Fuel Rail Pressure (FRP) sensor
- Fuel temperature sensor
- Water In Fuel (IF) sensor
- Fuel rail pressure control valve
- Fuel Pump Driver Module (FPM)
- Cylinder head temperature sensor
- Cylinder block temperature sensor
- Oil pressure and temperature sensor
- Glow plug control module
- Generator
- Active grille air shutter motor
- Variable Geometry Turbocharger (VGT) vane actuator
- Automatic Temperature Control Module (ATCM)
- Exhaust Gas Recirculation (EGR) valve - High Pressure (HP)
- EGR pressure sensor - Low Pressure (LP) EGR
- Charge air temperature sensor (EGR cooler outlet)
- Charge air temperature sensor (Charge air cooler)
- Exhaust gas temperature sensor - pre catalytic converter
- Exhaust gas temperature sensor - post catalytic converter
- Pre Selective Catalyst Reduction (SCR) NOx sensor module (NAS only)
- Post SCR NOx sensor module (EU6 and NAS only)
- Diesel Exhaust Fluid (DEF) tank module (EU6 and NAS only)
- DEF heater control unit (EU6 and NAS only)
- Gear selector position switch - Manual transmission only
- Clutch pedal position sensor - Manual transmission only
- Reverse switch - Manual transmission only
- Clutch Bottom Of Travel (BOT) switch - Manual transmission only
- Transmission Control Switch (TCS) - Automatic transmission only
- Transmission Control Module (TCM) - Automatic transmission only
- Brake vacuum switch.
Outputs:
- Fuel injector (4 off)
- Fuel metering valve
- Fuel rail pressure control valve
- Oil pressure control solenoid
- FPM
- Electric throttle
- Electric thermostat
- Engine cooling fan control module
- Variable Camshaft Timing (VCT) solenoid
- Variable coolant pump - shroud solenoid control
- Glow plug control module
- Generator
- VGT vane actuator
- ATCM
- Active air grille shutter motor
- Heated Oxygen Sensor (HO2S)
- HP EGR valve
- LP EGR valve
- EGR cooler by-pass valve solenoid (EU4 and NAS only)
- DEF tank module (EU6 and NAS only)
- DEF heater control unit (EU6 and NAS only)
- Transmission Control Module (TCM) - Automatic transmission only.
The PCM is connected to the vehicle harnesses via 2 connectors. The PCM contains data processors and memory microchips. The output signals to the actuators and sensors are in the form of ground paths provided by driver circuits within the PCM. The PCM driver circuits produce heat during normal operation and dissipate this heat via the ribbed casing.
The PCM performs self-diagnostic routines and stores fault codes in its memory. These fault codes and diagnostics can be accessed using an approved diagnostic system. If the PCM is to be replaced, the new PCM is supplied 'blank' and must be configured to the vehicle using an approved diagnostic system. A 'flash' Electrically Erasable Programmable Read Only Memory (EEPROM) allows the PCM to be externally configured, using an approved diagnostic system, with market specific or new tune information. The current engine tune data can be accessed and read using an approved diagnostic system.
When a new PCM is equipped, it must be synchronized to the Body Control Module/Gateway Module (BCM/GWM) assembly using an approved diagnostic system. PCM's cannot be 'swapped' between vehicles.
The PCM is connected to the engine sensors which allow it to monitor the engine operating conditions. The PCM processes these signals and determines the actions necessary to maintain optimum engine performance in terms of driveability, fuel efficiency and exhaust emissions. The memory of the PCM is programmed with instructions for how to control the engine, this known as the strategy. The memory also contains data in the form of maps which the PCM uses as a basis for fueling and emission control. By comparing the information from the sensors to the data in the maps, the PCM is able to calculate the various output requirements. The PCM contains an adaptive strategy which updates the system when components vary due to production tolerances or ageing.
Some sensors receive a regulated voltage supplied by the PCM. This avoids incorrect signals caused by voltage drop during cranking.
The PCM receives a vehicle speed signal on the High Speed (HS) Controller Area Network (CAN) powertrain systems bus from the Anti-lock Brake System (ABS) control module. Vehicle speed is an important input to the PCM strategies. The ABS control module derives the speed signal from the wheel speed sensors. The frequency of this signal changes according to road speed. The PCM uses this signal to determine the following:
- How much to reduce engine torque during gear changes on vehicles with manual transmission. (Vehicles with automatic transmission obtain the information from the TCM)
- When to permit speed control operation
- To control the operation of the speed control system
- Implementation of the idle strategy when the vehicle is stationary.