Input Signals: Notes

Fig 1: Identifying Input Signals

Courtesy of VOLVO CARS OF NORTH AMERICA.

Sensors and functions which are different to previous types are marked in bold text .

Number	Component	Information type/explanation
3/1	Ignition switch + 50 supply	Provides early information to the Engine Control Module (ECM) to prepare for start.
3/4	Cruise control lever	Gives information about selected speed to engine control module (ECM) via the electronic throttle module to control the throttle. The cruise control software in integrated into the engine control module (ECM).
3/9	Stop (brake) lamp switch	Informs engine control module (ECM) that the car is braking. The signal is a safety feature in addition to the brake pedal sensor. The engine control module (ECM) carries out a range test between the signals from both sources.
4/30 4/6	ECC MCC	Provides information if the air conditioning (A/C) is switched on or not. The engine control module (ECM) controls connection/disconnection of the compressor dependent on load, engine speed (RPM), engine coolant temperature, air conditioning (A/C) pressure.
7/6	Oil pressure switch	Provides information about engine oil pressure. The information is sent on to the Can and Driver information Module which lights the warning lamp.
7/8	air conditioning (A/C) pressure sensor (linear)	Provides information using a linear signal about any pressure changes on the high-pressure side. Depending on the pressure the engine control module (ECM) can activate the engine cooling fan (FC) at high/low speed and shut off the air conditioning (A/C) compressor. The engine control module (ECM) can also provide information about low volume in the air conditioning (A/C) system.
7/15	Front heated oxygen sensor (HO2S) (linear signal)	New signal characteristics. Provides information about the oxygen level in the exhaust gases upstream of the catalytic converter.
7/16	Engine coolant temperature sensor	Provides information about engine coolant temperature (ECT). Located in the thermostat housing on the front edge of the engine.
7/17	Mass air flow (MAF) sensor (heated film principle)	Provides information about the intake air mass. Has no resistor for the intake air temperature is complemented instead by a separate sensor 7/77 downstream of the charge air cooler (CAC).
7/21	Camshaft position (CMP) sensor	New signal characteristics. Provides information about cylinder intake and compression phase. Gives shorter starting time, approximately 0.5 seconds.
7/23 7/24	Knock sensor (KS) 1 Knock sensor (KS) 2	Provides information if the engine knocks. The engine control module (ECM) always knows each cylinders exact position from the new camshaft position (CMP) sensor. A turbocharged engine can be subjected to greater pressure variations in combustion chamber and must therefore have signals from 2 knock sensors (KS).
7/25	Engine speed (RPM)/position sensor	Provides information about the crankshaft position and engine speed (RPM). Has flywheel adaptation for mechanical faults/damage. Like M 4.4
7/51	Accelerator pedal (AP) position sensor	Provides information about current throttle opening. The signal is sent via two separate cables at the same time, one analog signal and one digital signal.
7/53	Low pressure sensor AC	Provides information about pressure changes on the low pressure side.
7/73	Engine coolant level switch	Provides information about engine coolant level. The information is sent further to the Can and Driver information Module which lights the low engine coolant level warning lamp.
7/77	Manifold absolute pressure (MAP) sensor	Provides information about the intake air actual temperature after the charge air cooler (CAC). Used for boost pressure control. The sensor is used together with intake air pressure sensor 7/81.
7/81	Manifold absolute pressure (MAP) sensor	Provides information about the intake air actual pressure after charge air cooler (CAC). The most important sensor for boost pressure control. The sensor is used together with intake air temperature sensor 7/77.
7/82	Rear heated oxygen sensor (HO2S)	Provides information about the oxygen level downstream of the catalytic converter (TWC) front section. Compared to previous versions it operates faster and can also affect the fuel/air mix to a greater extent.
7/84	Fuel tank pressure sensor	Provides information about pressure changes in the fuel tank system. Used for leak diagnostic.
7/95	Ambient air pressure sensor(located in engine control module (ECM)	Provides information about ambient air pressure. Affects injected fuel quantity at cold start at high altitude and leak diagnostic.
7/105	Ambient air temperature sensor	Provides information about ambient air temperature. The signal is used to switch off the leak diagnostic in cold weather.
7/123	Clutch pedal position sensor	Provides information that the clutch pedal is depressed and that the throttle should close. Used in certain markets to connect the so called Interlock function via VGLA which inhibits the starter motor. Also disconnects the cruise control.
7/124	Brake pedal sensor (located in the brake servo)	Provides information that the brake pedal is depressed and that the throttle should be closed in case of serious faults in the Electronic throttle system in order to move to idling speed when the brake pedal is depressed. The signal is used to disconnect the cruise control.
CAN	CAN communication	Exchange of information between the Engine Control Module (ECM) and the following units: ABS, TCM, CAN and driver module, electronic throttle module and DLC.