System Overview: Signals

The table below summarizes the input signals to and output signals from the Engine Control Module (ECM). The signal types are divided into directly connected signals, serial communication and controller area network (CAN) communication. The illustrations below (Fig 1 and Fig 2) displays the same information with the Volvo component designations.

Input signals	Output signals
Directly connected:	Directly connected:
Ignition switch (3/1) Transmission Control Module (TCM) (4/28) Air conditioning (A/C) pressure sensor (7/8) Air conditioning (A/C) pressure sensor (8/119) Stop lamp switch (3/9) Accelerator pedal (AP) position sensor (7/51) Throttle position (TP) sensor (via electronic throttle unit) (6/120) Camshaft position sensor, intake (7/172) Camshaft position sensor, exhaust (7/173) Engine coolant temperature (ECT) sensor (7/16) Engine speed (RPM) sensor (7/25) Fuel pressure sensor (7/156) Knock sensor (KS) (7/24) Mass air flow (MAF) sensor (7/17) Manifold absolute pressure (MAP) sensor (7/81) Oil pressure switch (7/6) Front heated oxygen sensor (HO2S) (7/15) Center heated oxygen sensor (HO2S) (certain markets only) (7/187) Rear heated oxygen sensor (HO2S) (7/82) Leak diagnostic unit (certain markets only) (6/67). Clutch pedal switch (3/271)	Air conditioning (A/C) relay (2/22) Electronic throttle unit (6/120) Engine cooling fan (FC) control module (4/71) Evaporative emission system (EVAP) valve (8/18) Injectors (8/6-8/10) Fuel pump control module - fuel pump (FP) (4/83)-(6/33) Ignition coils (20/3-20/7) Leak diagnostic unit including pre-heating (certain markets only) (6/67) Front heated oxygen sensor (HO2S), preheating (7/15) Center heated oxygen sensor (HO2S), preheating (certain markets only) (7/187) Rear heated oxygen sensor (HO2S), preheating (7/82) Starter motor relay (2/35) Main relay (system relay) (2/32) Camshaft reset valve (CVVT), intake (8/19).
Via LIN communication:	Via LIN communication:
Alternator control module (ACM) (6/26) (2005-) fault status magnetization for charging. Premair sensor (7/200) (2006-) (certain markets only): radiator temperature fault status.	Alternator control module (ACM) (6/26) (2005-) requested voltage for charging. Premair sensor (7/200) (2006-) (certain markets only): the request about the temperature and fault status.
Via Controller Area Network (CAN) communication:	Via Controller Area Network (CAN) communication:
Central electronic module (CEM) (4/56): outside temperature clutch pedal position accelerator pedal (AP) position (from the analog signal from the accelerator pedal (AP) position sensor) quantity of fuel in the tank the time since the engine was switched off request for increased idle speed request for battery charging (2005-) charging status (2005-). Brake control module (BCM) (4/16): brake pedal position the vehicle speed active control function front wheel spin to detect "rough roads" torque limiting request. Climate control module (CCM) (3/112): air conditioning (A/C) compressor request request for increased fan speed request for lowest permitted idle speed evaporator temperature. Transmission control module (TCM) (4/28): torque limiting request transmission oil temperature selected gear position "Lock-up" status (engaged/disengaged) request for lowest permitted idle speed gear ratio torque losses in the transmission. Steering wheel module (SWM) (3/254): request for cruise control steering angle. Combustion preheater module (CPM) (4/7): engine coolant heater status (on/off).	Central electronic module (CEM) (4/56): request for fuel pump (FP) engine speed load immobilizer codes cruise control status (on/off) alternator control module (ACM) load (2005-) alternator control module (ACM) fault status (2005-). Climate control module (CCM) (3/112): air conditioning (A/C) compressor status atmospheric pressure engine coolant temperature (ECT) engine speed engine status (on/off). Transmission control module (TCM) (4/28): selected gear position load cruise control status (on/off) engine coolant temperature (ECT) engine speed the position of the accelerator pedal (AP) brake pedal status (pressed/released) speed set in the cruise control engine status (on/off) "kickdown" request. Driver information module (DIM) (5/1): engine coolant temperature (ECT) warning texts related to the engine control module (ECM) engine speed cruise control status (on/off) calculated fuel consumption engine status (on/off) oil pressure status oil level time for service. Electrical power steering module (EPS) (4/99): engine speed engine status (on/off). Brake control module (BCM) (4/16): torque after transmission engine speed brake pedal status (pressed/released) the position of the accelerator pedal (AP) engine status (on/off). Combustion preheater module (CPM) (4/7): atmospheric pressure.

Fig 1: Identifying Engine Control Module & Components (1 Of 2)

Courtesy of VOLVO CARS CORPORATION

Fig 2: Identifying Engine Control Module & Components (2 Of 2)

Courtesy of VOLVO CARS CORPORATION