Checking Wake-Up Signal
The control module makes three attempts to activate a screen by transmitting a high signal on the cable as a wake-up signal to the screen in question. This takes place according to the following pattern, on the condition that the screen does not reply. Normally only one wake-up signal is sent for the screen to wake up.
If the pattern below appears, the screen is not responding.
Later software. Software, version.
- High voltage (approx. 11.5 V) for approx. one second.
- Low voltage (approx. 0 V) for approx. three seconds.
- High voltage (approx. 11.5 V) for approx. one second.
- Low voltage (approx. 0 V) for approx. three seconds.
- Constant high voltage.
Older software.
- High voltage (approx. 11.5 V) for approx. one second.
- Low voltage (approx. 0 V) for approx. one second.
- High voltage (approx. 11.5 V) for approx. one second.
- Low voltage (approx. 0 V) for approx. 10 seconds.
- Constant high voltage.
Measurement of wake-up signal.
When the ignition is on, the rear seat entertainment module (RSE) performs a simple internal system-check and starts the start-up procedure with the screens.
- Measure wake-up signal at the screen. Measure from the rear side of a suitable connector. Do not damage the terminals in the connector. Measure signal that goes to the screen that does not answer the wake-up calls.
- Switch on the ignition. Lighting in the DVD-player's buttons is activated.
- Note voltage of the wake-up signal.
Other information
- see SIGNAL SPECIFICATION, REAR SEAT ENTERTAINMENT MODULE (RSE), GENERATION 4.2
- see CHECKING WIRING AND TERMINALS
Is there any wake-up signal?
Rear seat entertainment module (RSE) (DVD-player) has not established contact with one or both screens. Follow the procedure below to check which screen has not responded.
Switch off the system before connecting/disconnecting a connector.
- Turn off the ignition.
- Connect a voltmeter between the cable for the wake-up signal to right screen and ground. Measure wake-up signal at the screen. Measure from the rear side of a suitable connector. Do not damage the terminals in the connector.
- Switch on the ignition. Wait approximately 10 seconds.
Check the voltage of the wake-up signal. Note voltage of the wake-up signal.
- Then measure the wake-up signal of the left screen. Note voltage of the wake-up signal.
| Left screen | Right screen | Options | |
|---|---|---|---|
| Voltage is continually high (approx. 11.5 V). | Voltage is continually high (approx. 11.5 V). | Communication established with both screens. | |
| Voltage is high (approx. 11.5 V) but goes down to approx. 0 V every 10 seconds. | Voltage is approx. 0 V. | No communication established with left screen. | 1. |
| Voltage is continually high (approx. 11.5 V). | Voltage is high (approx. 11.5 V) but goes down to approx. 0 V every 10 seconds. | No communication established with right screen. | 1. |
| Voltage is continually high (approx. 11.5 V). | Voltage is approx. 0 V. | Probable open circuit on wake-up signal for right screen. | 2. |
| Voltage is approx. 0 V. | Voltage is approx. 0 V. | Probable open circuit on wake-up signal for left screen. | 2. |
| Voltage is high (approx. 11.5 V) but goes down to approx. 0 V every 10 seconds. | Voltage is high (approx. 11.5 V) but goes down to approx. 0 V every 10 seconds. | Probable fault in CAN communication with screens. | 3. |
Select an option as set out in the table above.