Possible DTC

No audio system illumination

Using the M-MDS

U3003:16

Without using M-MDS (On-board diagnostic test mode)

09:Er20

Possible cause

• Illumination turned off by panel light control switch operation

• Open or short circuit in TNS signal wiring harness

• Poor connection of audio unit connector, terminal damage

• Audio unit malfunction

STEP

INSPECTION

ACTION

1

• Has the panel light control switch been operated?

Yes

Go to the next step.

No

The system is normal. Explain to the customer that the illumination is turned off by the panel light control switch operation.

2

• Disconnect the audio unit connector (24-pin) and inspect the continuity between the audio unit wiring harness-side connector terminal 1E (TNS) and the ground.

• Is there continuity?

Yes

Repair or replace the short circuit in the suspect wiring harness. After repair the harness, replace with the appropriate standard fuse.

No

Go to the next step.

3

• Inspect the connection of the audio unit connector (24-pin).

• Inspect both the audio unit and wiring harness-side connector terminal 1E for poor connection (such as damaged/pulled-out pins, corrosion).

• Are all the pins normal?

Yes

Go to the next step.

No

If poor connection of audio unit connector:

• Securely connect the audio unit connector.

If the audio unit side connector is damaged:

• Replace the audio unit.

  (See AUDIO UNIT REMOVAL/INSTALLATION.)

If the wiring harness-side connector is damaged:

• Repair or replace the pins and/or the connector.

4

• Connect the audio unit connector (24-pin).

• Switch the ignition to ACC.

• Inspect the voltage at the audio unit connector terminal 1E (TNS).

• Is the voltage B+ when the light switch is turned to the TNS position?

Yes

Replace the audio unit.

(See AUDIO UNIT REMOVAL/INSTALLATION.)

No

Repair or replace the suspect wiring harness (TNS signal).