Powertrain Control Module (Pcm)
| ITEM | DESCRIPTION |
|---|---|
| 1 | Powertrain Control Module (PCM) |
| 2 | Mounting bracket |
The 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
- Brake pedal switch
- Glow plug control module
- Clutch pedal position sensor
- Clutch Bottom Of Travel (BOT) switch
- Automatic Temperature Control Module (ATCM)
- Reverse switch
- Fuel Pump Driver Module (FPDM)
- Diesel Exhaust Fluid (DEF) tank module
- DEF heater control unit
- Transmission Control Switch (TCS) - Automatic transmission only
- Ambient Air Temperature (AAT) sensor
- Transmission Control Module (TCM) - Automatic transmission only
- Water in fuel sensor
- Gear selector position switch - Manual transmission only
- Generator
- Starter motor
- Active grille air shutter motor
- Engine Coolant Temperature (ECT) sensor - Radiator outlet
- Engine cooling fan control module
- Heated Oxygen Sensor (HO2S)
- Variable Camshaft Timing (VCT) solenoid
- Fuel rail pressure control valve
- Fuel rail pressure sensor
- Fuel temperature sensor
- Mass Air Flow (MAF)/Intake Air Temperature (IAT) sensor
- Electric throttle
- Cylinder head temperature sensor
- Oil pressure and temperature sensor
- Variable coolant pump - shroud position
- Variable Geometry Turbocharger vane actuator
- Exhaust gas temperature sensor - pre catalytic converter
- Exhaust gas pressure sensor
- Manifold Absolute Pressure and Temperature (MAPT) sensor
- Exhaust Gas Recirculation (EGR) valve - High Pressure (HP)
- Charge air temperature sensor (EGR cooler outlet)
- Charge air temperature sensor (Charge air cooler)
- ECT sensor - electric thermostat housing
- Oil pressure control solenoid
- Exhaust gas temperature sensor - post catalytic converter
- Cylinder block temperature sensor
- Post Selective Catalyst Reduction (SCR) Nox sensor module (EU6 and NAS only)
- Pre SCR Nox sensor module (NAS only)
- EGR pressure sensor - Low Pressure (LP) EGR
- Brake vacuum sensor.
- Post Selective Catalyst Reduction (SCR) soot sensor module (NAS only)
- Crankcase pressure sensor (NAS only)
Outputs:
- Heated Oxygen Sensor (HO2S)
- Variable Camshaft Timing (VCT) solenoid
- Fuel injector (4 off)
- EGR cooler bypass valve solenoid (EU4 and NAS only)
- Variable coolant pump - shroud solenoid control
- Variable Geometry Turbocharger vane actuator
- HP Exhaust Gas Recirculation (EGR) valve
- LP EGR valve
- Fuel metering valve
- Fuel rail pressure control valve
- Electric thermostat
- Glow plug control module
- Accelerator Pedal Position (APP) sensor
- Automatic Temperature Control Module (ATCM)
- Fuel Pump Driver Module (FPDM)
- Diesel Exhaust fluid (DEF) tank module
- DEF heater control unit
- Generator
- Active air grille shutter motor
- Transmission Control Module (TCM) - Automatic transmission only
- Electric throttle
- Engine cooling fan control module.
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 fitted, 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 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 ABS 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 Transmission Control Module (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.