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The purpose of this document is to identify which component and/or wire could be
the reason for loosing audio through all input methods. The way the infotainment
system is designed is to protect the amplifier from internal permanent damage in the
event of a fault on one of the components. As an example, if the system identifies
there is fault with one of the speakers or wiring, the audio output will stop to protect
the amplifier from permanent damage.

Find below a list of possible items that can cause permanent loss of audio via FM/AM,
DAB, SiriusXM Radio, Navigation prompts or media player through Bluetooth:

= Speaker shorting to ground or Vbatt

= Speaker wiring shorting to ground or Vbatt
= Loss of Vbatt or ground to the DAC module
= DAC cable shorting

= Amplifier

= Head Unit

The test below varies in some steps depending on the speaker system installed to
the vehicle (i.e. 4, 8 or 12 speakers),

1. Check fuse F9 3A in the facia fuse box. This supplies power to the DAC cable

If OK proceed to step 2, if not ok replace fuse and retest. If fuse fails again, check for
the cause

2. Check the RJ45 connection AUOO5 onto the HU. Remove, check and re-connect

If OK proceed to step 3. If not OK, resolve the poor connection and retest the audio
system

Care Point: Steps 3 to 5 apply only on vehicles installed with the 12 speakers system.
If the vehicle is fitted with the 4 or 8 speaker system, proceed directly to step 6.

Steps 3 to 5 are only applicable to 12 speakers system

3. Ensure the ignition is OFF and car fully asleep. Remove both A-pillar trims so the
tweeters are not touching anything and then switch the ignition ON and check if the
audio has returned

If the audio is recovered, then apply foam tape behind each speaker to insulate from
the trim

If the issue is still present proceed to step 4
4. Gain access to the amplifier, the test below will confirm which side is causing the loss
of audio:

Disconnect connector MB259 blue connector

MB259

Then disconnect the power supply connector MB260 and wait for 30 seconds

Then reconnect connector MB260
oS ' °

MB260

Now check if the audio has returned to left hand speakers only. If audio has returned,
check to confirm which speaker or associated wiring is causing the short circuit and
therefore the loss of audio

If the problem remains, reconnect connector MB259

Now disconnect connector MB258 grey connector

MB258

Then disconnect the power supply connector MB260 and wait for 30 seconds
Then reconnect connector MB260

Now check if the audio has returned to right hand speakers only. If audio has returned,
need to confirm which speaker or associated wiring is causing the short circuit and
therefore the loss of audio

5, Check connector IMBAMP white connector, check pin 1 for 12 volts and pin 6 for
ground. If no 12 volts present, check fuse F9 again that was checked at step 1. This
is Vbatt supply for the DAC module. If no ground, check ground GRND21, which is also
the ground for the amplifier
° IMBAMP c

Step 6 is only applicable to 4 or 8 speakers system

6. As previously mentioned Steps 3 to 5 are only applicable for 12 speakers system, so
for vehicles fitted with 4 or 8 speaker, you need to check the wiring of the speakers
if shorting to Vbatt or ground with a use of multimeter. This is because all the
speakers are connected through two connectors (MB261 and MB262) so it is not
possible to isolate sides and test as previously done. As a result, check for short
to Vbatt and ground at connectors MB261 and MB262 and the relevant speakers

7. Once the above steps have been completed, if a speaker or its wiring is not shorting
to Vbatt or ground, the next step will be to check the AC output from the DAC cable

8. Disconnect DACO1 connector from the amplifier - note the connector is different
according to the type of amplifier fitted

DACO1 for 12 Speakers Amplifier

DAC01

DACO1 for 4 or 8 Speakers Amplifier

9, Use the multimeter and set to AC volts

Care Point: Steps 10 to 12 apply only on vehicles installed with the
12 speakers system. If the vehicle is fitted with the 4 or 8 speaker system, proceed
directly to step 13.

Steps 10 to 12 are only applicable to 12 speakers system

10. At the DACO1 connector go across pins 3 and 13 with the multimeter.

11. Raise and lower the volume on the IRIS and monitor the AC voltage. Ensure a radio
station is selected so that audio is being transmitted from the HU

12. Repeat the same test across pins 4 and 14,5 and15,6 and18

Steps 13 to 14 are only applicable to 4 and 8 speakers system

13. At the DACO1 connector go across pins 7 and 15 with the multimeter.

14, Raise and lower the volume on the IRIS and monitor the AC voltage. Ensure a radio
station is selected so that audio is being transmitted from the HU

15, Repeat the same test across pins 8 and16

16. If the AC voltage does not vary while the volume is increased / decreased, the DAC
cable is faulty and needs replacing

17, If the testing above does not find the cause for the loss of audio, please raise a
Technical Request with your test results

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