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.
Central Locking (2001-2004): Signals
The chart below summarizes the input signals to and output signals from the different control modules for the lock function. The signal types are divided into directly connected signals, serial communication and control area network (CAN) communication.
| Directly connected input signals from the sensors / switches to the control module: | Directly connected output signals to the controlled components / functions from the control module: |
Brake control module (BCM) / ABS control module
, (4/16)
|
Central electronic module (CEM)
(4/56)
|
Central electronic module (CEM)
(4/56)
|
The driver's door module
(3/126)
|
The climate control module
(3/112)
|
The passenger door module
(3/127)
|
The driver's door module
(3/126)
|
Rear electronic module
(4/58)
|
The passenger door module
(3/127)
|
SRS control module
(4/9)
|
Rear electronic module
(4/58)
|
| Received information to control modules via Controller Area Network (CAN): | Transmitted information to control modules via Controller Area Network (CAN): |
| The central electronic module (4/56) receives from: The brake control module (ABS-control module) (4/16)
The climate control module (3/112)
Driver's door module (DDM) (3/126)
Passenger door module (3/127)
Rear electronic module (4/58)
Upper electronic module (4/70)
|
The central electronic module (4/56) transmits to: The driver information module (5/1)
Driver's door module (DDM) (3/126)
Passenger door module (3/127)
Rear electronic module (4/58)
|
| Driver information module (3/126) receives from: The central electronic module (CEM) (4/56)
|
The brake control module (ABS-control module) (4/16) transmits to: The central electronic module (CEM) (4/56)
|
| Driver information module (5/1) receives from: The central electronic module (CEM) (4/56)
|
Driver's door module (DDM) (3/126) transmits to: The central electronic module (CEM) (4/56)
|
| Passenger door module (3/126) receives from: The central electronic module (CEM) (4/56)
|
The passenger door module (3/126) transmits to: The central electronic module (CEM) (4/56)
|
| The rear electronic module (4/58) receives from: The central electronic module (CEM) (4/56)
|
Rear electronic module (4/58) transmits to: The central electronic module (CEM) (4/56)
|
| The upper electronic module (4/70) transmits to: The central electronic module (CEM) (4/56)
|
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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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