Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2003 Volvo S40FACTORY OEM SERVICE PROCEDURE
Signal specification Model year -2000
| Breakout box terminal | Control module terminal | Signal type | Ignition on | Other |
|---|---|---|---|---|
| #A1 | #A1 | Signal ground, control module | Ulow | - |
| #A2 | #A2 | Control voltage for locking the childlock motors. | Locking: Ubat | For cars with 2 stage unlocking: Unlocking the fuel tank filler cover. |
| #A3 | #A3 | Input signal, from the hood switch | Hood closed: Ulow Hood open: Ubat |
Grounded when the hood is closed |
| #A4 | #A4 | Input signal, lock impulse from the central locking switch | Locking: Ulow | Grounded when the switch is depressed |
| #A5 | #A5 | Not used | - | - |
| #A6 | #A6 | Input signal, Unlocking impulse from the central locking switch | Unlocking: Ulow | Grounded when the switch is depressed |
| #A7 | #A7 | Input signal, lock impulse from the childlock switch | Locking: Ulow | Grounded when the switch is depressed |
| #A8 | #A8 | Signal, data from the receiver, ID code | ID code | - |
| #A9 | #A9 | Input signal, signal strength from the receiver | R/F separation | - |
| #A10 | #A10 | Input signal, unlocking after collision | Normal status: Ubat | - |
| #A11 | #A11 | Input signal, code signal from the immobilizer | - | - |
| #A12 | #A12 | Control voltage to the left hand turn signal lamp | Turn signal lamp lit: Ubat | - |
| #A13 | #A13 | Control voltage to the right hand turn signal lamp | Turn signal lamp lit: Ubat | - |
| #A14 | #A14 | Control voltage for deadlock motors on the passenger side | Unlocking from deadlock position: Ubat | - |
| #A15 | #A15 | Control voltage for deadlock motors on the right hand side | Unlocking from deadlock position: Ubat | For cars with 2 stage unlocking: Control voltage for unlocking the driver's door |
| #A16 | #A16 | Input signal, lock impulse from the control switch in the driver's door lock unit | Locking: Ulow | Grounded when the key is turned to the locking position. For cars not equipped with a remote control: Unlocking impulse from the control switch in the driver's door. |
| #A17 | #A17 | Input signal, alarm signal from the tilt sensor | Alarm signal: Ulow | Alarm signal when the reference angle is exceeded |
| #A18 | #A18 | Input signal, unlocking impulse from the control switch in the driver's door lock unit | Unlocking: Ulow | Grounded when the key is turned to the unlocking position |
| #A19 | #A19 | Input signal from the trunk lid switch lock unit | Trunk lid open: Ulow Trunk lid closed: Ubat |
Grounded when the trunk lid is open |
| #A20 | #A20 | Not used | - | - |
| #A21 | #A21 | Input signal, Unlocking impulse from the childlock switch | Locking: Ubat | Also Output signal for childlock switch indication |
| #A22 | #A22 | Input signal, diagnostic signal from the sensors | Sensors active: Ulow | - |
| #A23 | #A23 | Input signal, door switch in the driver's door lock unit | Open door: Ulow Closed door: Ubat |
Grounded when the door is open |
| #A24 | #A24 | Output signal, interior lighting | Interior lighting lit: Ulow Interior lighting out: Ubat |
Lights the interior lighting when the signal is grounded |
| #A25 | #A25 | Output signal, courtesy lighting | - | Bridged to terminal #A23 |
| #A26 | #A26 | 30-supply (power supply from battery) | Ubat | Power supply for the turn signal lamp |
| #A27 | #B1 | 30-supply (power supply from battery) | Ubat | Power supply for electronics and lock motors |
| #A28 | #B2 | output signal, Control voltage for lock motors, passenger side doors and trunk lid or tailgate | Locking: Ubat | Cars equipped with the deadlock function, also control voltage for deadlock motors |
| #A29 | #B3 | Power supply to the tilt sensor | Sensor active: Ubat | Connected to the tilt sensor terminal 30 input signal |
| #A30 | #B4 | Output signal, indicator LED | LED lit: Ubat LED unlit: Ulow |
Ground extinguishes the LED |
| #A31 | #B5 | Input signal from the door switch in the passenger door lock unit | Door open: Ulow Closed door: Ubat |
Grounded when the door is open |
| #A32 | #B6 | Input signal from the door switch in the left rear door lock unit | Door open: Ulow Closed door: Ubat |
Grounded when the door is open |
| #A33 | #B7 | Input signal from the door switch in the right rear door lock unit | Door open: Ulow Closed door: Ubat |
Grounded when the door is open |
| #A34 | #B8 | Input signal from the ignition switch for ignition on or off | Ignition on: Ubat Ignition off: Ulow |
- |
| #A35 | #B9 | Input signal, indication signal from the childlock switch motors | Both rear doors locked in the child safe position: Ulow. One of the rear passenger doors is not locked: Ubat |
- |
| #A36 | #B10 | Input signal from the key warning switch on the ignition switch | Key in the ignition switch: Ubat Key out: Ulow |
NOTE: For EU/OS models the signal for the key in the ACC position or not. |
| #A37 | #B11 | Control voltage to the central locking motors on the driver's side | Unlocking: Ubat | - |
| #A38 | #B12 | Control voltage to the central locking motors on the passenger side | Unlocking: Ubat | - |
| #A39 | #B13 | Control voltage to the central locking motors on the driver's side | Locking: Ubat | - |
| #A40 | #B14 | Output signal, alarm signal to the siren | Alarm signal: Ulow | Warning signal. Triggers the siren |
| #A41 | #B15 | Output signal to the monitor sensors | Monitoring on: Ulow Monitoring off: Ubat |
Sets the sensors to the monitoring mode |
| #A42 | #B16 | Output signal, control signal for the receiver | - | - |
| #A43 | #B17 | Not used | - | - |
| #A44 | #B18 | Not used | - | - |
| #A45 | #B19 | Diagnostic lead C-link, Volvo on-board diagnostic (OBD) system | Diagnostic link | - |
| #A46 | #B20 | Output signal, Unlocking impulse for the central locking relay motor for the trunk lid | Unlocking trunk lid: Ubat | NOTE: EU/OS models: Output signal when the alarm is activated, for future use |
| #A47 | #B21 | Output signal, Signal to the door open warning lamp | Lamp lit: Ulow | - |
| #A48 | #B22 | Control voltage for unlocking the childlock motors. | Unlocking: Ubat | For cars with 2 stage unlocking: Locking the fuel tank filler cover. |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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