RDC Transmitter, Rear Left

RDC Transmitter, Rear Left

RDC transmitter, rear left
The RDC transmitter is a component of the Tyre Pressure Monitor (RDC).
In total, 4 RDC transmitters are installed (front left, front right, rear left and rear right). The 4 RDC transmitters are identical components.

The tyre pressure monitor is a system for monitoring the tyre pressure while the vehicle is being driven. It is offered exclusively in the USA (legal requirement) and as an optional extra in Canada. At the request of the RDC control module (in cycles of 54 seconds), a message is queried via the RDC transmitters (125 kHz) by each wheel electronics system (mounted in the wheel drop centre). The message is then sent across a high-frequency transmission path (433 MHz) to the RDC antenna.

Among other things, this message contains the following information:
- Tyre pressure
- Tyre air temperature
- Battery status of the wheel electronics system

The received radio signal are converted into a digital signal in the RDC antenna. This digital signal is forwarded on the bus to the RDC control module.

Functional description
The RDC control module sends a request to the RDC transmitters as a digital signal. Each RDC transmitter has its own electronics as well as its own data line to the RDC control module. In each RDC transmitter, the digital signal is converted into a radio signal. Subsequently, the RDC transmitters send the request telemetrically to the wheel electronics systems in the wheels.







Structure and inner circuit
All 4 pins at each plug-in connection are used. The outside pins are earth connections. The inner pins are power supply and signal cable. The two earth connection are connected on a board in the electronic module. Only 3 cables are used in the wiring harness.







Pin assignments

Pin Explanation
Kl. 31 Terminal 31, earth connection
12 V 12 Volts, power supply
SIG Signal line
Kl. 31 Terminal 31, earth connection

Target values
Observe the following target values for the RDC transmitters:

Variable Value
Voltage range 8 to 18 V
Current consumption (passive) 10 mA
Current consumption (active) 230 mA
Transmission frequency 125 ± 6 kHz
Radio data rate < 0.5 kBaud
Temperature range -40 to 105 °C

Diagnosis instructions

Failure of the component:
If a RDC transmitter fails, the following behaviour is to be expected:
- Fault memory entry in the RDC control module
- Check Control message
- The RDC indicator and warning light lights up

No liability can be accepted for printing or other faults. Subject to changes of a technical nature