LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Volvo >> 2003 >> XC70 >> Repair and Diagnosis >> External Pages >> Different car >> Section 45 (Ignition And Control Systems - Specifications, Electrical/Electronic) >> Signal Specification, Engine Control Module (ECM) (B5244S; 2001-2002) >> Signal specification
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Signal specification

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2007 Volvo V70, 2006 Volvo V70, 2005 Volvo V70, 2004 Volvo V70, and 2003 Volvo V70. However, it is still accessible from the selected car via links, so may be relevant.

General 

All values given below are between the terminals stated in column 1 and breakout box terminal #B2. Control module terminals #A1-#A60 correspond to terminals #A1-#A60 on the breakout box, terminals #A61-#A70 correspond to terminals #B1-#B10 on the breakout box and terminals #B1-#B50 correspond to terminals #B10-#B60 on the breakout box.

NOTE:

It is important to connect the breakout box and check the ground terminals before taking readings.

HINT: If the numbering of the connector is different from the numbering on the breakout box, the connector number is given first, terminal #A61, followed by the breakout box number in brackets, (terminal #B1). Example: #A61 (#B1). 

U= DC voltage in volts (V) U A/C = AC voltage in volts (V)
Ubat = Battery voltage in volts (V) f = Frequency in Hertz (Hz)
Ulow = Voltage approximately 0 V %pulse = Pulse ratio (%)
t = Time in milliseconds (ms)    
Connector terminals #A1 - #A70

Terminal  Breakout box  Signal type  Ignition ON  Idle  Other 
#A1 (#A1) - - - -
#A2 (#A2) Control signal
Evaporative emission system (EVAP) valve
U = Ubat - PWM signal, during activation of the EVAP canister shut off valve
#A3 (#A3) - - - -
#A4 (#A4) Signal (+)
Intake temperature sensor (integrated in the mass air flow (MAF) sensor)
- (+10°C) U=2.95 V
(+20°C) U=2.38 V
(+30°C) U=1.93 V
(+40°C) U=1.58 V
-
#A5 (#A5) - - - -
#A6 (#A6) - - - -
#A7 (#A7) Signal to the control module for the engine cooling fan (FC) Pulse width modulation (PWM) signal
Ulow = 1.5 V
pulse ratio = 10 %-90 %
-
Uhigh = Ubat -1.5 V
f = 100 Hz
-
#A8 (#A8) - - - -
#A9 (#A9) - - - -
#A10 (#A10) - - - -
#A11 (#A11) Control signal
preheating rear heated oxygen sensor (HO2S)
U = Ubat Preheating off U = Ubat
Preheating U = Ulow
-
#A12 (#A12) Reset valve
camshaft
Pulse width modulation (PWM) signal
Utop = Ubat
t = 0.6 ms
pulse ratio = 14 %
Pulse width modulation (PWM) signal
Utop = Ubat -1 V
t = 2ms
pulse ratio = 50 %
The pulse ratio changes with engine speed (RPM)
#A13 (#A13) - - - -
#A14 (#A14) Control signal
injector 5
U = Ubat t=2-3 ms t increases with engine speed (RPM) and load
#A15 (#A15) Control signal
injector 3
U = Ubat tlow = 2-3 ms t increases with engine speed (RPM) and load
#A16 (#A16) Control signal
injector 1
U = Ubat tlow = 2-3 ms t increases with engine speed (RPM) and load
#A17 (#A17) - - - -
#A18 (#A18) Control signal
preheating front heated oxygen sensor (HO2S)
U = Ubat Preheating off U = Ubat
Preheating U = Ubat
-
#A19 (#A19) - - - -
#A20 (#A20) - - - -
#A21 (#A21) Signal
A/C pressure sensor
U=0.9 V (at approximately 20°C) - U increases with increased pressure in the system
#A22 (#A22) Mass air flow (MAF) sensor signal U = 0.58 V U = 1.33 V
Unloaded, engine at operating temperature
U increases with increasing air mass
#A23 (#A23) Signal
manifold absolute pressure (MAP) sensor
U=3.6 V
atmospheric pressure at sea level
- U increases with pressure in the intake pipe
#A24 (#A24) Signal (+)
Front heated oxygen sensor (HO2S) signal (+)
- λ=0.95 V<700 mV
λ=1.10 V<200 mV
-
#A25 (#A25) - - - -
#A26 (#A26) - - - -
#A27 (#A27) - - - -
#A28 (#A28) Signal
ignition discharge module (IDM) check, ignition coils
- - -
#A29 (#A29) Control signal
ignition coil no. 3
U = Ulow U=2.5 V
thigh = 2 ms
The frequency varies according to engine speed (RPM)
#A30 (#A30) Control signal
ignition coil no. 2
U = Ulow U=2.5 V
thigh = 2 ms
The frequency varies according to engine speed (RPM)
#A31 (#A31) Control signal
ignition coil no. 1
U = Ulow U=2.5 V
thigh = 2.5 ms
The frequency varies according to engine speed (RPM)
#A32 (#A32) - - - -
#A33 (#A33) Control signal
injector 4
U = Ubat tlow = 2-3 ms t increases with engine speed (RPM) and load
#A34 (#A34) Control signal
injector 2
U = Ubat tlow = 2-3 ms t increases with engine speed (RPM) and load
#A35 (#A35) - - - -
#A36 (#A36) Power ground
preheating, front heated oxygen sensor (HO2S)
U = Ulow - -
#A37 (#A37) Communication cable
control modules (CAN H)
- - Between the engine control module (ECM) and the throttle unit
#A38 (#A38) Control signal
stop lamp - switch
U = Ulow (not activated)
U = Uhigh (activated)
- Between the engine control module (ECM) and the throttle unit
#A39 (#A39) Oil pressure switch U = Ulow (no oil pressure) U = Ubat -
#A40 (#A40) Signal (+)
Engine coolant temperature (ECT) sensor
- (+20°C) U = 3.1 V
(+30°C) U = 2.6 V
(+80°C) U = 0.9 V
(+100°C) U = 0.5 V
-
#A41 (#A41) Signal (-)
Front λheated oxygen sensor (HO2S)
- λ= 1 when the current is approximately +0.2 mA Negative current when the fuel air mixture is rich. Range: [-12 mA, +12 mA]
#A42 (#A42) Signal (+)
Front λheated oxygen sensor (HO2S)
- λ= 1 when the current is approximately +0.2 mA Positive current when the fuel air mixture is lean Range: [-12 mA, +12 mA]
#A43 (#A43) Signal, gas pressure sensor, regulator - - Applies only to CNG and only certain versions
#A44 (#A44) - - - -
#A45 (#A45) Signal (+)
Knock sensor (KS) 2 rear
- - Built in resistance 200 kΩ in the sensor
#A46 (#A46) Signal (+)
Knock sensor (KS) 1, front
- - Built in resistance 200 kΩ in the sensor
#A47 (#A47) Signal (+)
Camshaft sensor
U≈5 V or U=Ulow f≈35 Hz
U ≈ 2.5 V
The frequency increases with engine speed (RPM)
#A48 (#A48) Signal (+)
Flywheel sensor
U=2.5 V U = sine wave voltage
Utop = 3.5 V
Uoffset = 2.5 V
-
#A49 (#A49) - - - -
#A50 (#A50) Control signal
ignition coil no. 5
U = Ulow U=2.5 V
thigh = 2 ms
The frequency varies according to engine speed (RPM)
#A51 (#A51) Control signal
ignition coil no. 4
U = Ulow U=2.5 V
thigh = 2 ms
The frequency varies according to engine speed (RPM)
#A52 (#A52) - - - -
#A53 (#A53) Power ground 3 Ulow - -
#A54 (#A54) Power ground 2 Ulow - -
#A55 (#A55) Communication cable
control modules (CAN L)
- - Between the engine control module (ECM) and the throttle unit
#A56 (#A56) Control signal
accelerator pedal (AP) position sensor, pulse width modulation (PWM) signal
Utop = 12 V
t = 4ms
pulse ratio = 8 %-88 %
- Between the engine control module (ECM) and the throttle unit
#A57 (#A57) Power supply, camshaft position (CMP) sensor U =5 V - -
#A58 (#A58) Voltage supply manifold absolute pressure (MAP) sensor, air conditioning (A/C) pressure sensor, gas pressure sensor U =5 V - Gas pressure sensor, governor applies only to CNG and only certain versions
#A59 (#A59) - - - -
#A60 (#A60) Signal ground
mass air flow (MAF) sensor
U = Ulow - -
#A61 (#B1) Signal ground intake temperature sensor, engine coolant temperature (ECT) sensor, rear heated oxygen sensor (HO2S), gas pressure sensor U = Ulow - Gas pressure sensor, governor applies only to CNG and only certain versions
#A62 (#B2) Power ground 1 U = Ulow - -
#A63 (#B3) - - - -
#A64 (#B4) Signal (-)
Knock sensor (KS) 1 and 2
- - Built in resistance 200 kΩ in the sensor
#A65 (#B5) Signal ground
the camshaft position (CMP) sensor
U = Ulow - -
#A66 (#B6) Signal ground
flywheel sensor
U = Ulow - -
#A67 (#B7) - - - -
#A68 (#B8) - - - -
#A69 (#B9) Control signal
preheating front heated oxygen sensor (HO2S)
U = Ubat Preheating off U = Ubat
Preheating U = Ubat
B+ from the system relay
#A70 (#B10) Power supply U = Ubat - B+ from the system relay
Connector terminals #B1 - #B50

Terminal 
Data
Breakout box  Signal type  Ignition ON  Engine idling  Other 
#B1 (#B11) Communication cable
control modules (CAN L)
- - Data communication,
the high speed network
#B2 (#B12) - - - -
#B3 (#B13) - - - -
#B4 (#B14) Signal ground
intake manifold air temperature sensor
fuel tank pressure sensor
clutch pedal sensor
brake pedal sensor
U = Ulow - -
#B5 (#B15) Signal ground
accelerator pedal (AP) position sensor
U = Ulow - -
#B6 (#B16) - - - -
#B7 (#B17) - - - -
#B8 (#B18) Coolant level sensor U = Ulow - -
#B9 (#B19) Power supply
accelerator pedal (AP) position sensor, analog sensor
U =5 V - -
#B10 (#B20) Power supply
fuel tank pressure sensor
U =5 V - -
#B11 (#B21) 30-supply (power supply from battery) U = Ubat - -
#B12 (#B22) - - - -
#B13 (#B23) Control modules communication cable (CAN H) - - Data communication,
the high speed network
#B14 (#B24) - - - -
#B15 (#B25) Signal
clutch pedal sensor
U=3.3 V (unaffected)
U = 2.2 V (fully
depressed, 100 mm)
- Varies depending on the position of the clutch pedal
#B16 (#B26) Signal
brake sensor
U = 4.4 V (unaffected)
U = 3.9 V (25 mm depressed)
- Varies depending on the position of the brake pedal
#B17 (#B27) Signal
accelerator pedal (AP) position sensor, analog signal
U=0.4 V (idle)
U=4.4 V (wide open throttle (WOT))
- Varies depending on the position of the accelerator pedal (AP)
#B18 (#B28) - - - -
#B19 (#B29) - - - -
#B20 (#B30) - - - -
#B21 (#B31) - - - -
#B22 (#B32) Diagnostic lead C-link U=90% of Ubat If a generic
fault-tracing instrument is connected to the data link connector (DLC), other values apply
-
#B23 (#B33) Signal (+)
crank, +50 supply
U = Ulow U = Ulow U = Ubat at crank
#B24 (#B34) - - - -
#B25 (#B35) Signal (+)
accelerator pedal (AP) position sensor, PWM signal
Utop = Ubat
t = 4 ms
pulse ratio = 8-88%
- Between the accelerator pedal (AP) position sensor and the engine control module (ECM)
#B26 (#B36) Signal (+)
stop lamp switch
U = Ubat when the brake pedal is depressed
U = Ulow when the brake pedal is not depressed
- -
#B27 (#B37) - - - -
#B28 (#B38) - - - -
#B29 (#B39) Signal
outside temperature sensor
(0°C) U = 3.99 V
(+10°C) U = 3.53 V
(+20°C) U = 3.01 V
(+30°C) U = 2.47 V
- Temperature range: [-50°C, +120°C]
#B30 (#B40) - - - -
#B31 (#B41) Signal from the fuel tank pressure sensor U = 2.5 V at 1 kPa negative pressure
U=3.3 V at atmospheric pressure (0 kPa overpressure)
U = 4.1 V at 1kPa overpressure
- -
#B32 (#B42) Reconnected signal from the stepper motor during gas power - - Measures the control value backwards from terminal #B50
#B33 (#B43) - - - -
#B34 (#B44) - - - -
#B35 (#B45) - - - -
#B36 (#B46) - - - -
#B37 (#B47) Signal
ignition ON, +15-supply
U = Ubat - -
#B38 (#B48) System relay
control signal
U = Ulow U = Ulow Relay activated: U = Ulow
Relay not activated: U = Ubat
The system relay runs on (2-5 minutes)
#B39 (#B49) Control signal for the fuel shut off valve during retardation Valve active
U = Ulow
Valve disabled
U = Ubat
- PWM signal during control of the fuel shut-off valve
Only gas operation
#B40 (#B50) Control signal
EVAP canister shut-off valve
U=3.82 V - -
#B41 (#B51) Control signal to the fuel shut off valve for LPG U = Ubat valve active = Ulow
valve disabled = Ulow
The engine control module (ECM) grounds the relay controlling the LPG valve during gas operation
#B42 (#B52) - - - -
#B43 (#B53) - - - -
#B44 (#B54) Control signal
A/C activation
U = Ubat (not activated)
U = Ulow (activated)
- -
#B45 (#B55) Control signal
fuel pump activation
Pulse width modulation (PWM) signal - Control signal to the central electronic module (CEM) to control the fuel pump (FP)
#B46 (#B56) Control signal
malfunction indicator lamp (MIL)
U = Ulow U = Ubat (not activated)
U = Ulow (activated)
-
#B47 (#B57) - - - -
#B48 (#B58) Control signal
engine start inhibiting
U = Ulow (activated)
U = Uhigh (not activated)
- Certain markets only.
The engine can only be started with the clutch pedal depressed (U = Ulow)
#B49 (#B59) - - - -
#B50 (#B60) Control signal for the stepper motor during gas operation - - Normal range of control approximately 16%-83%
Only gas operation