Hyundai Tucson Quiz
Body Electrical System

Description and Operation

In this manual: Body Electrical System
General Information — 17Engine Mechanical System — 51Engine Electrical System — 26Emission Control System — 23Engine/Fuel Control System — 44Clutch System — 12MANUAL TRANSMISSION SYSTEM — 12AUTOMATIC TRANSMISSION SYSTEM — 42Four-Wheel Drive (4WD) System — 14Drive Shaft and Axle — 22Suspension System — 30Steering System — 16Restraint — 21Braking System — 47Body Work (Interior and Exterior) — 145Body Electrical System — 162Heating, Ventilation and Air Conditioning — 39
13steps
~78min
3/5difficulty
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General Description, Installation

RPAS (Rear Parking Assist System) is an electronic assist device that warns the driver to be careful during parking or low-speed driving. The sensors use ultrasonic waves to detect objects near the vehicle. RPAS includes four RPS sensors that detect obstacles and transmit the results separately to the BCM via communication. The BCM determines the alarm level through the transmitted communication message from the slave sensors, then sounds the buzzer or transmits data for display.
System Operation Specification
  1. INITIAL Mode
    1. System initialization time is 500 ms after ALL1 ON with the shift lever in R.
    2. RPAS recognizes the sensor cover and sets the sensor ID during initialization.
    3. RPAS activates each sensor, then performs diagnosis once. BCM initialization is complete.
    4. If diagnosis is complete and the sensor does not send an error message, the RPAS start buzzer operates normally.
    5. If an error is received from the sensors, the RPAS start buzzer does not operate, but the fault signal is displayed for some time. If there is a display option, the warning signal is also indicated above.
    6. The sensor fault buzzer sounds once, but the sensor fault status remains displayed until the fault is corrected.
  2. NORMAL MODE
    1. LIN communication starts and is maintained after ALL1 ON with the shift lever in R.
    2. The BCM sends a request message to each sensor to check the initial system status, and the four sensors respond in time. At this time, if there are no problems, the alarm starts 500 ms after the shift lever is moved to R, at 300 ms intervals.
    3. After initialization, normal mode starts 100 ms after the end of the alarm output.
    4. The obstacle alarm is divided into 3 levels. The first and second levels sound intermittently, and the third level sounds continuously.
    5. Effective vehicle speed of RPAS is less than 10 km/h.
    6. Refer to the "Digital PAS Project LIN Communication" section for more detailed communication specifications.
  3. Measurement conditions: PVC pole (diameter 75 mm, length 1 m), normal temperature.
  4. Objects detected within the following distance ranges (measured directly in front of the sensor): 61 cm (24.0 in) ~ 120 cm (47.2 in): ± 15 cm (5.9 in); 31 cm (12.2 in) ~ 60 cm (23.6 in): ± 15 cm (5.9 in); Within 30 cm (11.8 in): ±10 cm (3.9 in)
Detection Zone / Horizontal Detection Zone / Vertical Detection Zone / Distance Measurement

Direct measurement

Both transmission and reception are performed by the sensor (RL, RCL, RCR, RR during operation of each sensor).

Indirect measurement

(RCL → RL, RCL → RCR, RCR → RCL, RCR → RR are performed in order.) With two or three sensors, one of them sends a transmission while the others receive a reply.

Direct and indirect measurement at the same time.

With two or three sensors, one sensor performs transmission and reception, and the others only perform reception.
RPAS Alarm System: When an RPAS sensor detects an object, a warning is issued by an audible alarm device such as a buzzer. The RPAS sensor sends data to the BCM over the LIN line, and the BCM issues the audible warning for each RPAS sensor according to priority. It plays a role only when it sends a visible alarm device, such as the instrument cluster.
  • Display/Buzzer Information Processing Method. BCM Sensor. When information is received from the RL/RR sensors, the BCM directly processes each sensor's information related to the display function and buzzer output. For buzzer output from the CL/CR sensors, the BCM processes the central combined information, giving priority to both sensors.
Special System Operation: When the system is activated (after IGN ON and the vehicle is in R), the MICOM checks the channel of all sensors. When a fault is detected, it sounds a buzzer for 300 ms every 500 ms. If a fault is detected in at least one sensor, it sounds the buzzer corresponding to the faulty sensor instead of the initial start signal. The normal mode entry operation is as follows.
With the vehicle in reverse (R), the system operates as follows.
When the vehicle is out of reverse (R), the system operates as follows.
※ Permissible error on the waveform is ±10%. Alarm output characteristics classified by distance between sensors. Status logic according to alarm level priority is as follows. (Identical sensor)
* Determination of β value
  1. Sensor with lower priority disabled: α = 0 ms
  2. Sensor with lower priority is the 1st level warning: α < 340 ms
  3. Sensor with lower priority is the 2nd level warning: α < 170 ms
  4. Sensor with lower priority is the 1st level warning: β = 1700 ms
  5. Sensor with lower priority is the 2nd level warning: β = 1700 ms
  6. Sensor with lower priority is the 3rd level warning: β = 700 ms
  7. First Warning Zone (61–120 cm)
  8. Second warning zone (31 cm~80 cm)
  9. Third warning zone (less than 30 cm)
* Determination of β value: Distance-based alarm control is performed as follows. Visible Alarm Indicator Setting: When the transmission is shifted to R, the instrument cluster controls the indicator as shown in the following illustration. When the system detects an object, it immediately turns on the indicator. If the object disappears during RPAS detection, the indicator remains activated for 2 s before turning off. (However, when it changes from third-level alarm to no alarm, it activates the third-level alarm for two seconds and then turns off.)
  • It shows only the obstacle detection position.
  • At the third level alarm, the indicator flashes at one-second intervals.
  • In normal warning mode, the built-in display RCR/RCL
Standard Communication: This section defines the communication between RPAS and BCM. RPAS sends the object detection result and the sensor diagnostic result to the BCM in accordance with this document, and the BCM performs the role of activating the alarm. The indicator shows the transmitted position and alarm data in alarm mode; it finds the nearest data and first warns of the nearest data closer. (For example, if ArG is a first-level alarm and ArD is a third-level alarm, ArD has priority.)

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