Audio pinpoint tests

A1: CHECK THE VOLTAGE SUPPLIED TO THE AUDIO UNIT

1 Disconnect the C443 Audio Unit.

2 Enter the ACCESSORY position.

3 Using a digital multimeter, measure the voltage between C443 pin 1 of the audio unit, circuit 29-MD15 (orange/black), from the wiring side and "weight", and between pin 3 C443 of the audio unit, electrical circuit 75-MD15 (yellow/green), from the wiring side and "weight".

• Is the voltage more than 10 V in all cases?

→ Yes

Go to A2.

→ No

REPAIR Circuit 29-MD15 (orange/black) or electrical circuit 75-MD15 (yellow/green). CHECK the system is working properly.

A2: CHECK AUDIO UNIT GROUND CIRCUITS FOR OPEN

1 Enter the OFF position.

2 Using a DMM, measure the resistance between pin 6 C443 of the audio unit, circuit 91-MD15 (black/green), from the wiring side and "weight", and between pin 2 C443 of the audio unit, electrical circuit 91-MD34 (black/yellow), from the wiring side and "weight".

• Is the resistance less than 5 ohms in all cases?

→ Yes

INSTALL a new audio unit. CHECK the system is working properly.

→ No

REPAIR circuit 91-MD15 (black/green) or 91-MD34 (black/yellow). CHECK the system is working properly.

B1: CHECK ANTENNA CABLE SHIELD

1 Enter the OFF position.

2 Enter the OFF position.

3 Disconnect the Antenna cable.

4 Disconnect the antenna cable from the audio unit.

5 Using a digital multimeter, measure the resistance between the ground terminal of the antenna cable (screen), And "weight".

• Is the resistance less than 1 ohm?

→ Yes

Go to B2.

→ No

CLEAN and TIGHTEN the audio unit chassis ground and antenna base-to-body connection. If the problem persists, INSTALL a new antenna cable. CHECK the system is working properly.

B2: CHECK CENTER ANTENNA WIRE FOR OPEN CIRCUIT

1 Remove the antenna match.

2 Using a DMM, measure the resistance on the center wire between the ends of the antenna cable.

• Is the resistance less than 1 ohm?

→ Yes

Go to B3.

→ No

INSTALL a new antenna cable. CHECK the system is working properly.

B3: CHECK ANTENNA CABLE FOR SHORT CIRCUIT

1 Using a digital multimeter, measure the resistance between the antenna center wire and antenna ground (screen).

• Is the resistance over 10,000 ohms?

→ Yes

CLEAN and TIGHTEN the ground connections at the base of the antenna, on the body of the audio unit and wires "masses" battery to the body. If the problem persists, INSTALL a new audio unit. CHECK the system is working properly.

→ No

INSTALL a new antenna cable. CHECK the system is working properly.

C1: CHECK SPEAKER RESISTANCE

1 Disconnect the non-working speaker.

2 Using a DMM, measure the resistance between pin 1 and pin 2 of the non-working speaker on the element side.

• Is the resistance approximately 4.0 ohms?

→ Yes

Go to C2.

→ No

INSTALL a new speaker. CHECK the system is working properly.

C2: CHECK SPEAKER INPUT FOR SHORT CIRCUIT TO "MASSES"

1 Disconnect the C443 Audio Unit.

2 Using a DMM, measure the resistance between pin 1 of the inoperative speaker connector on the wiring side and "weight".

• Is the resistance over 10,000 ohms?

→ Yes

Go to C3.

→ No

REPAIR the speaker input circuit. CHECK the system is working properly.

C3: CHECK SPEAKER RETURN CIRCUIT FOR A SHORT TO "MASSES"

1 Using a DMM, measure the resistance between pin 2 of the inoperative speaker connector on the wiring side and "weight".

• Is the resistance over 10,000 ohms?

→ Yes

INSTALL a new speaker. CHECK the system is working properly. If the problem persists, INSTALL a new audio unit. CHECK the system is working properly.

→ No

REPAIR the speaker return circuit. CHECK the system is working properly.

D1: CHECK THE SPEAKER INPUT CIRCUIT FOR A SHORT TO "MASSES"

1 Enter the OFF position.

2 Disconnect the Audio Unit - C442.

3 Using a digital multimeter, measure the resistance between the following pins on the audio unit connector and "weight":

- (Front left speaker) pin 1 C442, electric circuit 8-MD10 (white/black), from the wiring side and "weight".

- (Rear left speaker) pin 3 C442, electrical circuit 8-MD11 (white/green), from the wiring side and "weight".

- (Front right speaker) pin 5 C442, electrical circuit 8-MD17 (white/red), from the wiring side and "weight".

- (Rear right speaker) pin 7 C442, electrical circuit 8-MD18 (white), from the wiring side and "weight".

• Is the resistance greater than 10,000 ohms in all cases?

→ Yes

Go to D2.

→ No

REPAIR the relevant circuit. CHECK the system is working properly.

D2: CHECK SPEAKER RETURN CIRCUIT FOR A SHORT TO "MASSES"

1 Using a digital multimeter, measure the resistance between the following pins on the audio unit connector and "weight":

- (Front left speaker) pin 2 C442, electrical circuit 10-MD10 (gray/black), from the wiring side and "weight".

- (Rear left speaker) pin 4 C442, electrical circuit 10-MD11 (grey/white), from the wiring side and "weight".

- (Front right speaker) pin 6 C442, electrical circuit 10-MD17 (gray/red), from the wiring side and "weight".

- (Rear right speaker) pin 8 C442, electrical circuit 10-MD18 (gray), from the wiring side and "weight".

• Is the resistance greater than 10,000 ohms in all cases?

→ Yes

INSTALL a new audio unit. CHECK the system is working properly.

→ No

REPAIR the relevant circuit. CHECK the system is working properly.

E1: CHECK SPEAKER RESISTANCE

1 Disconnect the non-working speaker.

2 Using a DMM, measure the resistance between pin 1 and pin 2 of the non-working speaker on the element side.

• Is the resistance approximately 4.0 ohms?

→ Yes

Go to E2.

→ No

INSTALL a new speaker (And). CHECK the system is working properly.

E2: CHECK RESISTANCE IN SPEAKER CIRCUIT WITH SPEAKER DISCONNECTED

1 Disconnect the Audio Unit - C442.

2Using a DMM, measure the resistance between the audio unit, C442, and the speaker connector pins corresponding to the non-working speaker (am).

- (Front left speaker) pin 1 C442, electric circuit 8-MD10 (white/black), wiring side, and pin 2 C937, circuit 8-MD28 (white), from the side of the electrical wiring.

- (Front left speaker) pin 2 C442, electrical circuit 10-MD10 (gray/black), wiring side, and pin 1 C937, electrical circuit 10-MD28 (gray), from the side of the electrical wiring.

- (Front right speaker) pin 5 C442, electrical circuit 8-MD17 (white/red), wiring side, and pin 2 C938, electrical circuit 8-MD28 (white), from the side of the electrical wiring.

- (Front right speaker) pin 6 C442, electrical circuit 10-MD17 (gray/red), wiring side, and pin 1 C938, electrical circuit 10-MD28 (brown), from the side of the electrical wiring.

- (Rear left speaker) pin 3 C442, electrical circuit 8-MD11 (white/green), wiring side, and pin 2 C939, circuit 8-MD29 (white/green), from the side of the electrical wiring.

- (Rear left speaker) pin 4 C442, electrical circuit 10-MD11 (grey/white), wiring side, and pin 1 C939, electrical circuit 10-MD11 (grey/white), from the side of the electrical wiring.

- (Rear right speaker) pin 7 C442, electrical circuit 8-MD18 (white), wiring side, and pin 2 C940, circuit 8-MD29 (white/green), from the side of the electrical wiring.

- (Rear right speaker) pin 8 C442, electrical circuit 10-MD18 (gray), wiring side, and pin 1 C940, electrical circuit 10-MD29 (grey/white), from the side of the electrical wiring.

• Is the resistance less than 5 ohms?

→ Yes

INSTALL a new speaker. CHECK the system is working properly. If the problem persists, INSTALL a new audio unit. CHECK the system is working properly

→ No

REPAIR the relevant circuit. CHECK the system is working properly.

F1: CHECK THE FUSE IN SERIES

1 Check the 3 amp fuse in series provided for the CD changer.

• Is the 3A fuse OK?

→ Yes

Go to F2.

→ No

INSTALL a new fuse. CHECK the system is working properly.

F2: CHECK WIRING FROM AUDIO UNIT TO CD CHANGER UNIT

1 Disconnect the CD changer - C465.

2 Disconnect the C464 Audio Unit.

3 Perform a CD changer box wiring test. For more information, refer to CD Changer Unit Wiring available in this section..

• Is the wiring from the audio unit to the CD changer unit correct?

→ Yes

Go to F3.

→ No

REPAIR or INSTALL new CD changer unit wiring. CHECK the system is working properly.

F3: CHECK THE FUNCTIONING OF THE CD CHANGER UNIT

1 Substitute with a known-good CD changer.

2 Check the replacement CD changer unit for proper operation.

• Are all functions of the CD changer working properly?

→ Yes

INSTALL a new CD changer For more information, refer to Checking the Items in this section. CHECK the system is working properly.

→ No

REMOVE the replacement CD changer. INSTALL the original CD changer. INSTALL a new audio unit. CHECK the system is working properly.

G1: CHECK THE AUDIO UNIT IS PROPERLY OPERATING WITHOUT USING THE REMOTE CONTROL

1 Operate the audio unit using the remote control.

• Does the audio unit work properly without using the remote control?

→ Yes

Go to G2.

→ No

INSTALL a new audio unit. For more information, refer to the Audio Block available in this section. CHECK the system is working properly.

G2: CHECK 8-MD26 CIRCUIT FOR OPEN

1 Disconnect the C447 Audio Unit.

2 Disconnect the Radio Remote Control - C437.

3 Using a digital multimeter, measure the resistance between pin 11 C447 of the audio unit, circuit 8-MD26 (white/black) from the wiring side, and pin 1 C437 radio remote control, electrical circuit 8-MD26 (white/black) from the wiring side.

• Is the resistance less than 5 ohms?

→ Yes

Go to G3.

→ No

REPAIR circuit 8-MD26. CHECK the system is working properly.

G3: CHECK 9-MD26 CIRCUIT FOR OPEN

1 Using a digital multimeter, measure the resistance between pin 12 C447 of the audio unit, circuit 9-MD26 (brown/yellow) from the wiring side, and pin 2 C437 radio remote control, electrical circuit 9-MD26 (brown/yellow) from the wiring side.

• Is the resistance less than 5 ohms?

→ Yes

INSTALL a new radio remote control. CHECK the system is working properly.

→ No

REPAIR circuit 9-MD26 (brown/yellow). CHECK the system is working properly.

pin 1

pin 1

Less than 5 ohm

pin 3

pin 3

Less than 5 ohm

pin 5

pin 5

Less than 5 ohm

Pin 6

Pin 6

Less than 5 ohm

Pin 7

Pin 7

Less than 5 ohm

Pin 8

Pin 8

Less than 5 ohm

Pin 9

Pin 9

Less than 5 ohm

Pin 10

Pin 10

Less than 5 ohm

pin 11

pin 11

Less than 5 ohm

Pin 12

Pin 12

Less than 5 ohm

CD Changer - C465

Negative multimeter wire

pin 1

"Weight"

Over 10,000 ohms

pin 3

"Weight"

Over 10,000 ohms

pin 5

"Weight"

Over 10,000 ohms

Pin 6

"Weight"

Over 10,000 ohms

Pin 7

"Weight"

Over 10,000 ohms

Pin 8

"Weight"

Over 10,000 ohms

Pin 9

"Weight"

Over 10,000 ohms

Pin 10

"Weight"

Over 10,000 ohms

pin 11

"Weight"

Over 10,000 ohms

pin 12

"Weight"

Over 10,000 ohms