Powertrain Control Module
The Powertrain Control Module (PCM) is located in the rear side corner of the engine compartment.
The PCM receives inputs from various sensors and output reference voltages and signal information to other sensors for engine control.
The PCM receives inputs from the following:
- Crankshaft Position (CKP) sensor
- Camshaft Position (CMP) sensor
- Brake pedal switch
- Glow plug control module
- HVAC Control Module
- Fuel Pump Driver Module (FPDM)
- Ambient Air Temperature (AAT) sensor
- Diesel Exhaust Fluid (DEF) tank module (if equipped)
- DEF heater control unit (if equipped)
- Transmission Control Switch (TCS) - Vehicles with automatic transmission only
- Transmission Control Module (TCM) - Vehicles with automatic transmission only
- Water In Fuel (WIF) sensor
- Clutch pedal position sensor - Vehicles with manual transmission only
- Clutch Bottom Of Travel (BOT) switch - Vehicles with manual transmission only
- Gear selector position switch - Manual transmission only
- Reverse switch - Vehicles with manual transmission only
- Generator
- Starter motor
- Active grille air shutter motor (if equipped)
- Radiator outlet Engine Coolant Temperature (ECT) sensor
- 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 Turbine (VGT) vane actuator
- Exhaust gas temperature sensor - pre catalytic converter
- Manifold Absolute Pressure and Temperature (MAPT) sensor
- Exhaust Gas Recirculation (EGR) valve - High Pressure (HP)
- Exhaust gas pressure sensor
- 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 (EU6 and NAS only)
- EGR pressure sensor - Low Pressure (LP) EGR
- Brake vacuum sensor
- Post Selective Catalyst Reduction (SCR) sensor module (EU6 and NAS only)
- Crankcase pressure sensor. (NAS only)
The PCM provides outputs to the following:
- Heated Oxygen Sensor (HO2S)
- Variable Camshaft Timing (VCT) solenoid
- Fuel injector (quantity 4)
- EGR cooler bypass valve solenoid (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
- HVAC Control Module
- 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) - Vehicles with 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. Cooling for the PCM is provided by a ribbed casing.
The PCM performs self-diagnostic routines and stores Diagnostic Trouble Codes (DTCs) in its memory. These DTCs and diagnostics can be accessed using the Jaguar Land Rover (JLR) approved diagnostic equipment. If the PCM is to be replaced, the new PCM is supplied 'blank'. The new PCM must be configured to the vehicle using the JLR approved diagnostic equipment. A 'flash' Electrically Erasable Programmable Read Only Memory (EEPROM) allows the PCM to be externally configured, with market specific or new tune information. The current engine tune data can be accessed and read using the JLR approved diagnostic equipment.
When the PCM is replaced, the new PCM must be synchronized to the Body Control Module/Gateway Module (BCM/GWM) using the JLR approved diagnostic equipment. 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 BCM/GWM receives a vehicle speed signal on the FlexRay bus from the Anti-lock Brake System (ABS) control module. The BCM/GWM provides the vehicle speed signal to the PCM on the FlexRay bus. 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:
- 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.