Inspection Procedure 4

INSPECTION PROCEDURE 4: On the Audio Screen, "E" cannot Proceed to Next Screen.










CIRCUIT OPERATION

The multi-center display unit receives information from the radio and CD player with CD changer [Vehicles with audio amplifier] or radio and CD player [Vehicles without audio amplifier] via M-bus communication to display the audio system operation condition.

TECHNICAL DESCRIPTION (COMMENT)

The audio system operation screen will be frozen if the multi-center display have received abnormal data from the radio and CD player with CD changer [Vehicles with audio amplifier] or radio and CD player [Vehicles without audio amplifier] via M-bus communication within 30 seconds. If the abnormal data is received further 30 seconds from that point, a message
"E" will be displayed.

TROUBLESHOOTING HINTS

- Malfunction of multi-center display unit
- Malfunction of radio and CD player with CD changer[ Vehicles with audio amplifier] or radio and CD player[ Vehicles without audio amplifier]
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Check of the display.





Q. Is "E" displayed?

YES Go to Step 2.

NO Go to Step 4.

STEP 2. Check radio and CD player with CD changer connector C-119 [Vehicles with audio amplifier] or radio and CD player connector C-118 [Vehicles without audio amplifier] and multi-center display unit connector C-06 for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q. Is radio and CD player with CD changer connector C-119[ Vehicles with audio amplifier] or radio and CD player connector C-118[ Vehicles without audio amplifier] and multi-center display unit connector C-06 in good condition?

YES Go to Step 3.

NO Repair or replace the component(s). Harness Connector Inspection.
Then go to Step 1.

STEP 3. Check the wiring harness between radio and CD player with CD changer connector C-119 (terminal 27, 28, 38 and 39) [Vehicles with audio amplifier] or radio and CD player connector C-118 (terminal 21, 22, 26 and 27) [Vehicles without audio amplifier] and multi-center display unit connector C-06 (terminal 8, 9, 7 and 10).





Q. Is the wiring harness between radio and CD player with CD changer connector C-119 (terminal 27, 28, 38 and 39)[ Vehicles with audio amplifier] or radio and CD player connector C-118 (terminal 21, 22, 26 and 27)[ Vehicles without audio amplifier] and multi-center display unit connector C-06 (terminal 8, 9, 7 and 10) in good condition?

YES Go to Step 4.

NO Repair the wiring harness and then go to Step 1.

STEP 4.Using the oscilloscope, check the M-BUS line.

(1)Connect the multi-center display unit connector C-06 and radio and CD player with CD changer connector C-119 [Vehicles with audio amplifier] or radio and CD player connector C-118 [Vehicles without audio amplifier].





(2)Connect the oscilloscope probe to terminal 10 of the multi-center display unit connector by backprobing.
(3)Turn the ignition switch to "ACC" position.
(4)Operate each of the radio and CD player with CD changer switches [Vehicles with audio amplifier] or radio and CD player switches[Vehicles without audio amplifier].

Q. Is a wave pattern displayed?

YES Go to Step 5.

NO Replace multi-center display unit and then go to Step 6.

STEP 5. Retest the system

Confirm that the audio operation screen is displayed normally.

Q. Is the check result satisfactory?

YES Intermittent malfunction How to Cope With Intermittent Malfunctions.
NO Replace radio and CD player with CD changer [Vehicles with audio amplifier] or radio and CD player [Vehicles without audio amplifier] and then go to Step 6.
STEP 6. Retest the system

Confirm that the audio operation screen is displayed normally.

Q. Is the check result satisfactory?

YES The procedure is complete.
NO Go to Step 1.