FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Volvo >> 2012 >> XC60 R Design AWD L6-3.0L Turbo VIN 90 B6304T4 >> Repair and Diagnosis >> Powertrain Management >> Relays and Modules - Powertrain Management >> Relays and Modules - Computers and Control Systems >> Engine Control Module >> Description and Operation >> Engine Control Module (ECM) >> Design >> Part 3

Part 3






Design

Fuel pump control module




The fuel pump control module is called the PEM (Pump Electronic Module). The function of the PEM is to supply the fuel pump with voltage and to control the power output of the fuel pump. When the power output of the pump is changed the fuel pressure/fuel flow is also changed.
The fuel pump control module is supplied with battery voltage by the fuel pump (FP) relay and is grounded in the car body. The fuel pump (FP) relay is controlled by the central electronic module (CEM) when requested by the engine control module (ECM).
The engine cannot be started if the power supply to the fuel pump control module is faulty because the fuel pump will not then be powered.
Fuel pump control module is controlled by Engine control module (ECM) via serial communication. Then the fuel pump control module controls the fuel pump by adding a pulse-width modulated (PWM) voltage on the fuel pump's ground cable.
This means that the voltage across the pump changes, and then also the fuel pump's output.
See also
There are no diagnostics for the fuel pump control module. The engine control module (ECM) has diagnostics for fuel pressure regulation and the associated components. See also: Fuel pressure control, diagnostics, B6304T4 Fuel Pressure Control, Diagnostics
The pulse width modulated (PWM) signal from the engine control module (ECM) to the fuel pump control module can be read off using the diagnostic tool.
The fuel pump control module is on the outside on the right-hand side of the fuel tank.

Emissions warning lamp




The emissions warning lamp in the Driver Information Module (DIM) has a warning symbol. This warning symbol varies depending on the market. The warning symbols are:
- Engine symbol" (not USA)
- "CHECK ENGINE" (MIL - Malfunction Indicator Lamp, only USA)
The warning lamp lights when the start control module (SCU) is activated to position II. The warning lamp will go out after approximately 15 seconds or if the engine is started when no fault is found in the engine management system.
If Readiness is not complete (certain diagnostic functions not completed), the warning lamp will flash instead of going out when the start control module (SCU) is in position II.
The warning lamp will light if there is a fault in one of the parameters in the engine management system. The warning lamp will also light in response to a request transmitted via the control area network (CAN) if there is a fault in the transmission control module (TCM) which affects emissions.

Electronic throttle unit




The electronic throttle unit, using the PWM control signal from the engine control module (ECM), regulates the amount of air for engine combustion. This is done using an electronically controlled shutter.
The aluminium electronic throttle unit consists of a round throttle disc on a spindle. The spindle is driven by a DC motor (damper motor), gear wheel and two springs; one for opening and one for return.
By changing the polarity of the power supply, the DC motor can be run in both directions. At one of the limit positions the throttle disc is closed so that minimal air can pass the throttle unit. In the other limit position, the throttle disc is parallel to the air flow. This provides maximum airflow through the electronic throttle unit.
Two permanent magnets in the gear sector on the throttle spindle are used to check the position of the throttle disc. The permanent magnets affect two throttle position (TP) Hall sensors in the cover. The analog signals from the two sensors are transmitted to the engine control module (ECM). The signals are offset. The engine control module (ECM) compares these signals with the stored desired values to check if they are plausible.
The electronic throttle unit is located on the engine intake manifold. In the event of a fault, the throttle unit must be replaced as a single unit.
The engine control module (ECM) can diagnose the electronic throttle unit.

Throttle position (TP) sensor
See Design, Electronic throttle unit.

Outside temperature sensor




The function of the outside temperature sensor is to detect the vehicle's ambient temperature. The ambient temperature is required so that the engine control module (ECM) can regulate, among other things:
- the engine cooling fan (FC)
- the air conditioning (A/C) compressor's displacement.
The ambient temperature is also used as a substitute value in the event of a fault in certain components or functions and to control certain diagnostic functions.
The engine control module (ECM) supplies other control modules with the current outside temperature by transmitting information on the controller area network (CAN).
The temperature sensor is a resistor with a negative temperature coefficient, so called NTC type. It is supplied with power from the control module.
The resistance in the sensor changes according to the ambient temperature of the vehicle. This provides the engine control module (ECM) with a signal of between 0-5 V. Low temperature results in high resistance (high voltage). High temperature results in low resistance (low voltage).
The outside temperature sensor is positioned in the left door mirror.
The engine control module (ECM) can diagnose the outside temperature sensor. The sensor value can be read off using the diagnostic tool.

Manifold absolute pressure (MAP) sensor, intake




The manifold absolute pressure (MAP) sensor detects quick pressure changes in the intake manifold after the throttle. The signal from the sensor is used by the engine control module (ECM) to supplement the mass air flow (MAF) sensor when calculating injection period.
Manifold absolute pressure (MAP) sensor, intake, is located on the upper part of the intake manifold.
The semi-conductor sensor is grounded in the control module and is supplied with power from the control module.
The resistance in the intake manifold moves the silicone membrane in the sensor, giving a signal of 0.5 - 4.5 V to the control module. Low pressure results in low voltage, high pressure gives high voltage.
The pressure sensor can be diagnosed by the engine control module (ECM) and the sensor signal can be read off.

Fuel pressure sensor / fuel temperature sensor




Overview
The fuel pressure, fuel temperature sensor is combined and consists of both the fuel pressure sensor and the fuel temperature sensor. The sensor detects the fuel pressure (the absolute pressure) and the temperature of the fuel in the fuel rail.
The fuel pressure sensor is located on the fuel rail's end.
The fuel pressure-/fuel temperature sensor can be diagnosed by the engine control module (ECM) and its signals (pressure and temperature) can be read off.
Fuel pressure sensor
The pressure sensor is a Piezo resistive type resistor, the resistance of which changes with the pressure. Depending on the pressure in the fuel rail, an analog signal of 0 - 5 V is transmitted to the engine control module (ECM). Low pressure results in low voltage, high pressure gives high voltage.
The engine control module (ECM) then uses this signal to adjust the pressure in the fuel rail using the fuel pump control module. See also
The pressure sensor is supplied with 5 V and grounded in the engine control module (ECM). The pressure sensor transmits a signal indicating the fuel pressure to the engine control module (ECM) on a separate cable.

Note! The absolute pressure is displayed when using parameter read outs to read off the fuel pressure. If there is no pressure at the fuel rail, the atmospheric pressure will be displayed.

Hint: The relative pressure (absolute pressure minus atmospheric pressure) is displayed when reading off the fuel pressure via a manometer connected to the fuel rail.

Fuel temperature sensor
The temperature sensor is an NTC sensor. The sensor is supplied with voltage (signal) from and grounded in the engine control module (ECM).
The resistance in the sensor changes according to the temperature of the fuel. This provides the engine control module (ECM) with a signal of between 0 - 5 V. Low temperature results in high voltage (high resistance). High temperature results in low voltage (low resistance).
The engine control module (ECM) uses the signal to calculate the volume of the fuel.

pro multis Credits:Operation CHARM About Operation CHARM