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.
Integrated Radar Sensor, Component Description - GF30.30-S-3313A
Model 447
With Code JA7 (Blind Spot Monitoring)
With Code XM7 (MOPF II)
Integrated radar sensor, Shown On Model 447.8
Integrated radar sensor, Shown On Model 447.8
The numbers on the pins indicate the pin numbering of the slots.
Overview
This document contains information on:
- General
- Function
- Reading in of signals
- Evaluate the input signals
- Output of signals
- Structure
General
The left rear Blind Spot Assist radar sensor (B161/3) and right rear Blind Spot Assist radar sensor (B161/4) are installed on the insides of the rear bumper.
Function
The left rear Blind Spot Assist radar sensor (B161/3) and right rear Blind Spot Assist radar sensor (B161/4) detect vehicles in the blind spot.
The left rear Blind Spot Assist radar sensor (B161/3) and right rear Blind Spot Assist radar sensor (B161/4) operate according to the "master-slave" principle. The "master function" is assumed by the right rear Blind Spot Assist radar sensor (B161/4). This means that the left rear Blind Spot Assist radar sensor (B161/3) transmits information via the periphery CAN (CAN PER) to the right rear Blind Spot Assist radar sensor (B161/4), which evaluates the information and forwards the requests or data via the periphery CAN (CAN PER) to the relevant control units.
The "Master function" is established by 2 additional ground connections (coding).
The left rear Blind Spot Assist radar sensor (B161/3) and right rear Blind Spot Assist radar sensor (B161/4) have the following additional tasks:
- Reading in of signals
- Evaluate the input signals
- Output of signals
- Structure
Reading in of signals
Reading in of signals
The right rear Blind Spot Assist radar sensor (B161/4) (master) reads in the following signals via the periphery CAN (CAN PER):
- Status information of the left rear Blind Spot Assist radar sensor (B161/3)
- Detection data of the left rear Blind Spot Assist radar sensor (B161/3)
- Status of circuit 15 from the electronic ignition lock control unit (EIS) (N73/8)
- "Circuit 61 ON" (engine running) from the CDI control unit (N3/40) (with engine 654) or ME control unit (N3/34) (with engine 254) via the engine CAN (CAN C1) to the powertrain control unit (N127) and then via the periphery CAN (CAN PER)
- Wheel rotation directions: direction of movement of the vehicle, from the Electronic Stability Program (ESP) control unit (N30/4) via suspension FlexRay to the electronic ignition lock control unit (EIS) (N73/8) and then via the periphery CAN (CAN PER)
- Wheel speeds from the Electronic Stability Program (ESP) control unit (N30/4) via suspension FlexRay to the electronic ignition lock control unit (EIS) (N73/8) and then via the periphery CAN (CAN PER)
- Vehicle speed from the Electronic Stability Program (ESP) control unit (N30/4) via suspension FlexRay to the electronic ignition lock control unit (EIS) (N73/8) and then via the periphery CAN (CAN PER)
- Status of the combination switch (S4) from the steering column tube module (MRM) control unit (N80) via suspension FlexRay to the electronic ignition lock control unit (EIS) (N73/8) and then via the periphery CAN (CAN PER)
- Status of Blind Spot Assist from the instrument cluster control unit (N133/1) via the user interface CAN 2 (CAN HMI2) to the electronic ignition lock control unit (EIS) (N73/8) and then via the periphery CAN (CAN PER) (model 447.8)
- Status of Blind Spot Assist from the instrument cluster (A1) via the user interface CAN 2 (CAN HMI2) to the electronic ignition lock control unit (EIS) (N73/8) and then via the periphery CAN (CAN PER) (model 447.6/7)
- Status of the trailer recognition system (with Code Q50 (removable trailer coupling ball head) or with Code Q22 (non-removable trailer coupling ball head)) from the trailer recognition control unit (AAG) (N28/1) via the vehicle interior CAN (CAN B) to the electronic ignition lock control unit (EIS) (N73/8) and then via the periphery CAN (CAN PER)
Evaluate the input signals
The input signals are evaluated by the microprocessor integrated in the right rear Blind Spot Assist radar sensor (B161/4) (master).
Output of signals
The right rear Blind Spot Assist radar sensor (B161/4) (master) transmits the following signals via the periphery CAN (CAN PER):
- Instrument cluster speaker request (H4/61) via the electronic ignition lock control unit (EIS) (N73/8), forwarded via the user interface CAN 2 (CAN HMI2) to the instrument cluster control unit (N133/1) (model 447.8)
- instrument cluster speaker request via the electronic ignition lock control unit (EIS) (N73/8), forwarded via the user interface CAN 2 (CAN HMI2) to the instrument cluster (A1) (model 447.6/7)
- Display request (A1p13) via the electronic ignition lock control unit (EIS) (N73/8), forwarded via the user interface CAN 2 (CAN HMI2) to the instrument cluster (A1) (model 447.6/7)
- Left Blind Spot Assist readiness and warning display request (M21/4e3) via the electronic ignition lock control unit (EIS) (N73/8), forwarded via the vehicle interior CAN (CAN B) to the left front door control unit (N69/3)
- Left Blind Spot Assist readiness and warning display request (M21/5e3) via the electronic ignition lock control unit (EIS) (N73/8), forwarded via the vehicle interior CAN (CAN B) to the right front door control unit (N69/4)
Structure
The left rear Blind Spot Assist radar sensor (B161/3) and right rear Blind Spot Assist radar sensor (B161/4) are ultra-wideband radar sensors with the following properties:
- Detection range s = 0.5 to 3 m, with a resolution of s = 0.04 m
- Detection angle: ∠ = 80° with angle measurement and ∠ = 140° with detection only (tracing)
- Carrier frequency f = 24 GHz
- Method of operation: short pulse method with f = 5 GHz bandwidth
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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.
