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:
- Anti-lock Brake System (ABS) control module
- Crankshaft Position (CKP) sensor
- Camshaft Position (CMP) sensor (2 Off)
- Brake pedal switch
- Transmission Control Module (TCM)
- Transmission Control Switch (TCS)
- Ambient Air Temperature (AAT) sensor
- Radiator outlet Engine Coolant Temperature (ECT) sensor
- Engine cooling fan control module
- Heated Oxygen Sensor (HO2S) (3 Off)
- Mass Air Flow and Temperature (MAFT) sensor
- Electric throttle - Throttle Position Sensor (TPS)
- Cylinder head temperature sensor
- Cylinder block temperature sensor
- Knock sensor (2 Off)
- Oil pressure and temperature sensor
- Oil pump control solenoid
- Variable coolant pump - Shroud position
- Manifold Absolute Pressure and Temperature (MAPT) sensor
- Engine Coolant Temperature (ECT) sensor - Electric thermostat housing
- Continuously variable valve lift assembly oil temperature sensor
- Fuel Rail Pressure and Temperature (FRPT) sensor
- Accelerator Pedal Position (APP) sensor.
The PCM provides outputs to the following:
- Electric throttle
- Fuel injector (4 Off)
- Ignition coil (4 Off)
- Variable Camshaft Timing (VCT) solenoid (2 Off)
- Purge valve
- Engine cooling fan control module
- Charge air coolant pump
- High Pressure (HP) fuel pump
- Fuel Pump Driver Module (FPDM)
- Compressor Recirculation Valve (CRV)
- Turbocharger wastegate actuator
- Heater element - Electric thermostat housing
- Auxiliary coolant pump
- Active engine mount solenoid
- Diagnostic Module Tank Leakage (DMTL) - North American Specification (NAS) vehicles only
- Variable coolant pump
- Piston cooling oil jets solenoid
- Continuously variable valve lift solenoid (4 Off).
The PCM is connected to the vehicle harnesses via two 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 and a cooling fan assembly.
The PCM performs self-diagnostic routines and stores Diagnostic Trouble Codes (DTCs) in its memory. These DTCs and diagnostics can be accessed using a Jaguar approved diagnostic equipment. If the PCM is to be replaced, the new PCM is supplied 'blank' and must be configured to the vehicle using a Jaguar 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 a Jaguar approved diagnostic equipment.
When a new PCM is fitted, it must be synchronized to the Body Control Module/Gateway Module (BCM/GWM) assembly using a Jaguar 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 assembly receives a vehicle speed signal on the FlexRay bus from the Anti-lock Brake System (ABS) control module. The BCM/GWM assembly 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.