DTC 74-40

AUDIO / VISUAL: AUDIO AND VISUAL SYSTEM: 74-40: Short in Speaker Circuit

DTC 74-40 - Short in Speaker Circuit

DESCRIPTION





This circuit has a fail-safe function.

- When a short in the speaker circuit is detected, all sound outputs are stopped.

WIRING DIAGRAM













INSPECTION PROCEDURE
HINT: After the inspection is completed, clear the DTCs.

PROCEDURE

1. CHECK VEHICLE EQUIPMENT

Vehicle equipment





B -- INSPECT STEREO COMPONENT AMPLIFIER
A -- Continue to next step.

2. INSPECT RADIO RECEIVER
(a) Disconnect the R3 and R4 receiver connectors.
(b) Clear DTC and recheck.
(c) Check if DTC 74-40 is output.
OK:
DTC 74-40 is not output.
NG -- REPLACE RADIO RECEIVER
OK -- Continue to next step.

3. CHECK OPERATION
(a) Reconnect the R3 and R4 receiver connectors.
(b) Check if DTC 74-40 is output.
OK:
DTC 74-40 is not output.
OK -- END
NG -- Continue to next step.

4. CHECK WIRE HARNESS (RADIO RECEIVER - SPEAKER)




(a) Disconnect the R3 and R4 receiver connectors.
(b) Disconnect the T6, T7, R11 and R12 speaker connectors.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

5. CHECK WIRE HARNESS (FRONT NO. 1 SPEAKER - FRONT NO. 2 SPEAKER)




(a) Disconnect the F12, F13, T6 and T7 speaker connectors.
(b) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

6. INSPECT FRONT NO. 1 SPEAKER




(a) Disconnect the F12 and F13 speaker connectors.
(b) Measure the resistance of the speaker.
Standard resistance:






NG -- REPLACE FRONT NO. 1 SPEAKER
OK -- Continue to next step.

7. INSPECT FRONT NO. 2 SPEAKER
(a) Check that the malfunction disappears when the speaker is replaced with a normal one.
OK:
Malfunction disappears.
HINT:
- Connect all the connectors to the front No. 2 speakers.
- When there is a possibility that either the right or left front speaker is defective, inspect by interchanging the right one with the left one.
- Perform the inspection above on both LH and RH sides.

NG -- REPLACE FRONT NO. 2 SPEAKER
OK -- Continue to next step.

8. INSPECT REAR NO. 1 SPEAKER




(a) Disconnect the R11 and R12 speaker connectors.
(b) Measure the resistance of the speaker.
Standard resistance:






NG -- REPLACE REAR NO. 1 SPEAKER
OK -- REPLACE RADIO RECEIVER
9. INSPECT STEREO COMPONENT AMPLIFIER
(a) Disconnect the S14 and S29 amplifier connectors.
(b) Clear DTC and recheck.
(c) Check if DTC 70-40 is output.
OK:
DTC 74-40 is not output.
NG -- REPLACE STEREO COMPONENT AMPLIFIER
OK -- Continue to next step.

10. CHECK OPERATION
(a) Reconnect the S14 and S29 amplifier connectors.
(b) Check that audio can be heard from the speaker.
OK:
Audio can be heard.
OK -- END
NG -- Continue to next step.

11. CHECK WIRE HARNESS (STEREO COMPONENT AMPLIFIER - SPEAKER)




(a) Disconnect the S14 and S29 amplifier connectors.
(b) Disconnect the C8, F12, F13, T6, T7, T8 and T9 speaker connectors.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

12. CHECK WIRE HARNESS (REAR NO. 1 SPEAKER - REAR NO. 2 SPEAKER)




(a) Disconnect the R11, R12, T8 and T9 speaker connectors.
(b) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

13. INSPECT FRONT NO. 1 SPEAKER




(a) Disconnect the F12 and F13 speaker connectors.
(b) Measure the resistance of the speaker.
Standard resistance:






NG -- REPLACE FRONT NO. 1 SPEAKER
OK -- Continue to next step.

14. INSPECT FRONT NO. 2 SPEAKER
(a) Check that the malfunction disappears when the speaker is replaced with a normal one.
OK:
Malfunction disappears.
HINT:
- Connect all the connectors to the front No. 2 speakers.
- When there is a possibility that either the right or left front speaker is defective, inspect by interchanging the right one with the left one.
- Perform the inspection above on both LH and RH sides.

NG -- REPLACE FRONT NO. 2 SPEAKER
OK -- Continue to next step.

15. INSPECT REAR NO. 1 SPEAKER




(a) Disconnect the R11 and R12 speaker connectors.
(b) Measure the resistance of the speaker.
Standard resistance:






NG -- REPLACE REAR NO. 1 SPEAKER
OK -- Continue to next step.

16. INSPECT REAR NO. 2 SPEAKER
(a) Check that the malfunction disappears when the speaker is replaced with a normal one.
OK: :
Malfunction disappears.
HINT:
- Connect all the connectors to the rear No. 2 speakers.
- When there is a possibility that either the right or left rear speaker is defective, inspect by interchanging the right one with the left one.
- Perform the inspection above on both LH and RH sides.

NG -- REPLACE REAR NO. 2 SPEAKER
OK -- Continue to next step.

17. INSPECT FRONT STEREO COMPONENT SPEAKER




(a) Disconnect the C8 speaker connector.
(b) Measure the resistance of the speaker.
Standard resistance:






NG -- REPLACE FRONT STEREO COMPONENT SPEAKER
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE