DTC 74-40

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

DTC 74-40 - Short in Speaker Circuit

DESCRIPTION





WIRING DIAGRAM









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

PROCEDURE

1. CHECK DTC
(a) Disconnect the R35, R36 and R39 amplifier connectors.
(b) Clear the DTC.
(c) Check if DTC 74-40 is output.
OK:
DTC 74-40 is not output.
NG -- REPLACE STEREO COMPONENT AMPLIFIER
OK -- Continue to next step.
2. CHECK DTC
(a) Reconnect the R39 amplifier connector.
(b) Check if DTC 74-40 is output.
OK:
DTC 74-40 is not output.
NG -- CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER - SPEAKER)
OK -- Continue to next step.
3. CHECK DTC
(a) Reconnect the R35 amplifier connector.
(b) Check if DTC 74-40 is output.
OK:
DTC 74-40 is not output.
NG -- CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER - SPEAKER)
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER - SPEAKER)




(a) Disconnect the R36 amplifier connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. INSPECT FRONT NO. 1 SPEAKER LH




(a) Disconnect the N12 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FRONT NO. 1 SPEAKER LH
OK -- Continue to next step.
6. INSPECT FRONT NO. 1 SPEAKER RH




(a) Disconnect the N4 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FRONT NO. 1 SPEAKER RH
OK -- Continue to next step.
7. INSPECT REAR HEADER SPEAKER LH




(a) Disconnect the S18 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE REAR HEADER SPEAKER LH
OK -- REPLACE REAR HEADER SPEAKER RH
8. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER - SPEAKER)




(a) Disconnect the R39 amplifier connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
9. INSPECT REAR NO. 2 SPEAKER LH




(a) Disconnect the O12 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE REAR NO. 2 SPEAKER LH
OK -- Continue to next step.
10. INSPECT FRONT NO. 3 SPEAKER




(a) Disconnect the M1 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FRONT NO. 3 SPEAKER
OK -- REPLACE STEREO COMPONENT SPEAKER
11. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER - SPEAKER)




(a) Disconnect the R35 amplifier connector.
(b) Disconnect the R24 ECU connector.*
(c) Disconnect the Q8 and Q3 speaker connectors.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT: *: w/ LEXUS Link System

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
12. INSPECT REAR NO. 2 SPEAKER RH




(a) Disconnect the O1 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE REAR NO. 2 SPEAKER RH
OK -- Continue to next step.
13. INSPECT REAR NO. 1 SPEAKER LH




(a) Disconnect the O21 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE REAR NO. 1 SPEAKER LH
OK -- Continue to next step.
14. INSPECT REAR NO. 1 SPEAKER RH




(a) Disconnect the O10 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE REAR NO. 1 SPEAKER RH
OK -- Continue to next step.
15. INSPECT REAR NO. 3 SPEAKER
(a) Check that the malfunction disappears when the speaker is replaced with a normal one.
OK:
DTC 74-40 is not output.
HINT:
- Connect all the connectors to the rear No. 3 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. 3 SPEAKER
OK -- Continue to next step.
16. INSPECT FRONT NO. 2 SPEAKER LH




(a) Disconnect the L9 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FRONT NO. 2 SPEAKER LH
OK -- Continue to next step.
17. CHECK VEHICLE EQUIPMENT
(a) Check if the vehicle is equipped with the LEXUS Link System.

Result





B -- REPLACE FRONT NO. 2 SPEAKER RH
A -- Continue to next step.
18. CHECK HARNESS AND CONNECTOR (MAYDAY ECU - STEREO COMPONENT AMPLIFIER AND FRONT NO. 2 SPEAKER RH)




(a) Disconnect the R35 amplifier connector.
(b) Disconnect the L84 speaker connector.
(c) Disconnect the R24 ECU connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
19. INSPECT FRONT NO. 2 SPEAKER RH




(a) Disconnect the L84 speaker connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE FRONT NO. 2 SPEAKER RH
OK -- REPLACE MAYDAY ECU