Nissan Sentra Service Manual: Dtc/circuit diagnosis

Power supply and ground circuit

Audio unit

Audio unit : diagnosis procedure

Regarding wiring diagram information, refer to av-25, "wiring diagram".

1.Check fuse

Check that the following fuses are not blown.

Are the fuses blown? Yes >> replace the blown fuse after repairing the affected circuit.

No >> go to 2.

2.Check power supply circuit

1. Turn ignition switch off.
2. Disconnect audio unit connector m43.
3. Check voltage between audio unit connector m43 and ground.

Is the inspection result normal? Yes >> go to 3.

No >> repair or replace harness or connectors.

3.Check ground circuit

1. Turn ignition switch off
2. Disconnect audio unit connector M44
3. Check continuity between audio unit connector m44 and ground.

Is the inspection result normal? YES >> Inspection End.

NO >> Repair or replace harness or connectors.

BluetoothВ® control unit

BluetoothВ® control unit : diagnosis procedure

Regarding wiring diagram information, refer to av-25, "wiring diagram".

1.Check fuse

Check that the following fuses are not blown.

Are the fuses blown? YES >> Replace the blown fuse after repairing the affected circuit.

NO >> GO TO 2.

2.Check power supply circuit

1. Turn ignition switch OFF.
2. Disconnect bluetoothВ® control unit connector m45.
3. Check voltage between BluetoothВ® control unit connector M45 and ground.

Is the inspection result normal? Yes >> go to 3.

No >> repair or replace harness or connectors.

3.Check ground circuit

1. Turn ignition switch off.
2. Check continuity between BluetoothВ® control unit connector M45 and ground.

Is the inspection result normal? Yes >> inspection end.

No >> repair or replace harness or connectors.

Front door speaker

Diagnosis procedure

1.Connector check

Check the audio unit and speaker connectors for the following:

• Proper connection
• Damage
• Disconnected or loose terminals

Is the inspection result normal? Yes >> go to 2 no >> repair the terminals or connectors.

2.Check front door speaker signal circuit continuity

1. Disconnect audio unit connector M43 and suspect front door speaker connector.
2. Check continuity between audio unit connector m43 and suspect front door speaker connector.

3. Check continuity between audio unit connector m43 and ground.

Is the inspection result normal? YES >> GO TO 3

NO >> Repair or replace harness or connectors.

3.Check front door speaker signal

1. Connect audio unit connector M43 and suspect front door speaker connector.
2. Turn ignition switch to ACC.
3. Push audio unit POWER switch.
4. Check signal between the terminals of audio unit connector M43.

Is the inspection result normal? YES >> Replace front door speaker. Refer to AV-60, "Removal and Installation".

NO >> Replace audio unit. Refer to AV-58, "Removal and Installation".

Front tweeter

Diagnosis procedure

Regarding wiring diagram information, refer to av-25, "wiring diagram".

1.Connector check

Check the audio unit and speaker connectors for the following:

• Proper connection
• Damage
• Disconnected or loose terminals

Is the inspection result normal? Yes >> go to 2 no >> repair the terminals or connectors.

2.Check front tweeter signal circuit continuity

1. Disconnect audio unit connector m43 and suspect front tweeter connector.
2. Check continuity between audio unit connector m43 and suspect front tweeter connector.

3. Check continuity between audio unit connector m43 and ground.

Is the inspection result normal? Yes >> go to 3

No >> repair or replace harness or connectors.

3.Check front tweeter signal

1. Connect audio unit connector m43 and suspect front tweeter connector.
2. Turn ignition switch to acc.
3. Push audio unit POWER switch.
4. Check signal between the terminals of audio unit connector m43.

Is the inspection result normal? Yes >> replace front tweeter. Refer to av-59, "removal and installation".

No >> replace audio unit. Refer to av-58, "removal and installation".

Rear speaker

Diagnosis procedure

Regarding wiring diagram information, refer to av-25, "wiring diagram".

1.Connector check

Check the audio unit and speaker connectors for the following:

• Proper connection
• Damage
• Disconnected or loose terminals

Is the inspection result normal? Yes >> go to 2

No >> repair the terminals or connectors.

2.Check rear speaker signal circuit continuity

1. Disconnect audio unit connector M43 and suspect rear speaker connector.
2. Check continuity between audio unit connector m43 and suspect rear speaker connector.

3. Check continuity between audio unit connector m43 and ground.

Is the inspection result normal? Yes >> go to 3

No >> repair or replace harness or connectors.

3.Check rear speaker signal

1. Connect audio unit connector m43 and suspect rear speaker connector.
2. Turn ignition switch to ACC.
3. Push audio unit POWER switch.
4. Check signal between the terminals of audio unit connector M43.

Is the inspection result normal? YES >> Replace rear speaker. Refer to AV-61, "Removal and Installation".

NO >> Replace audio unit. Refer to AV-58, "Removal and Installation".

BluetoothВ® voice signal circuit

Diagnosis procedure

Regarding Wiring Diagram information, refer to AV-25, "Wiring Diagram".

1.Check bluetoothВ® voice signal circuit continuity

1. Turn ignition switch OFF.
2. Disconnect audio unit connector M44 and BluetoothВ® control unit connector M45.
3. Check continuity between audio unit connector m44 and bluetoothВ® control unit connector m45.

4. Check continuity between audio unit connector M44 and ground.

Is inspection result normal? Yes >> go to 2.

No >> repair or replace harness or connectors.

2.Check bluetoothВ® voice signal ground circuit continuity

Check continuity between audio unit connector m44 and bluetoothВ® control unit connector m45.

Is inspection result normal? YES >> GO TO 3.

NO >> Repair or replace harness or connectors.

3.Check bluetoothВ® voice signal

1. Connect audio unit connector m44 and bluetoothВ® control unit connector m45.
2. Turn ignition switch to acc.
3. Press switch.


4. Check signal between the terminals of audio unit connector m44.

Is the inspection result normal? Yes >> replace bluetoothВ® control unit. Refer to av-68, "removal and installation".

No >> replace audio unit. Refer to av-58, "removal and installation".

BluetoothВ® control signal circuit

Diagnosis Procedure

Regarding wiring diagram information, refer to av-25, "wiring diagram".

1.Check control signal circuit continuity

1. Turn ignition switch off.
2. Disconnect BluetoothВ® control unit connector M45.
3. Check continuity between bluetoothВ® control unit connector m45 and ground.

Is the inspection result normal? YES >> Replace BluetoothВ® control unit. Refer to AV-68, "Removal and Installation".

NO >> Repair or replace harness or connectors.

Microphone signal circuit

Diagnosis procedure

Regarding wiring diagram information, refer to av-25, "wiring diagram".

1.Check harness between bluetoothВ® control unit and microphone

1. Turn ignition switch off.
2. Disconnect BluetoothВ® control unit connector M45 and microphone connector R4.
3. Check continuity between BluetoothВ® control unit connector M45 and microphone connector R4.

4. Check continuity between bluetoothВ® control unit connector m45 and ground.

Are continuity results as specified? Yes >> go to 2

NO >> Repair harness or connectors.

2.Check microphone power supply

1. Connect bluetoothВ® control unit connector m45 and microphone connector r4.
2. Turn ignition switch on.
3. Check voltage between microphone connector r4 and ground.

Is the voltage reading as specified? YES >> GO TO 3

No >> replace bluetoothВ® control unit. Refer to av-68, "removal and installation".

3.Check microphone signal

Check signal between terminals of bluetoothВ® control unit connector m45.

Were voltage readings as specified? Yes >> replace bluetoothВ® control unit. Refer to av-68, "removal and installation".

No >> replace microphone. Refer to av-69, "removal and installation".

Steering switch

Diagnosis procedure

Regarding wiring diagram information, refer to av-25, "wiring diagram".

With bluetoothВ®

1.Check steering wheel audio control switch resistance

1. Turn ignition switch off.
2. Disconnect combination switch (spiral cable) connector m79.
3. Check resistance between the terminals of combination switch (spiral cable) connector M79.

Is the inspection result normal? Yes >> go to 2.

No >> replace steering switches. Refer to av-62, "removal and installation".

2.Check harness between bluetoothВ® control unit and combination switch (spiral cable)

1. Disconnect BluetoothВ® control unit connector M45 and combination switch (spiral cable) connector M80.
2. Check continuity between bluetoothВ® control unit connector m45 and combination switch (spiral cable) connector m80.

3. Check continuity between bluetoothВ® control unit connector m45 and ground.

Is the inspection result normal?

Yes >> go to 3.

No >> repair or replace harness or connectors.

3.Check combination switch (spiral cable)

Check continuity between combination switch (spiral cable) connectors m79 and m80.

Is the inspection result normal? Yes >> go to 4.

No >> replace combination switch (spiral cable). Refer to sr-16, "removal and installation".

4.Check harness between bluetoothВ® control unit and audio unit

1. Disconnect audio unit connector m43.
2. Check continuity between bluetoothВ® control unit connector m45 and audio unit connector m43.

3. Check continuity between BluetoothВ® control unit connector M45 and ground.

Is the inspection result normal? Yes >> replace audio unit. Refer to av-58, "removal and installation".

No >> repair or replace harness or connectors.

Without bluetoothВ®

1.Check steering wheel audio control switch resistance

1. Turn ignition switch off.
2. Disconnect combination switch (spiral cable) connector M79.
3. Check resistance between the terminals of combination switch (spiral cable) connector m79.

Is the inspection result normal? Yes >> go to 2.

No >> replace steering switches. Refer to av-62, "removal and installation".

2.Check combination switch (spiral cable)

Check continuity between combination switch (spiral cable) connectors M79 and M80.

Is the inspection result normal? Yes >> go to 3.

No >> replace combination switch (spiral cable). Refer to sr-16, "removal and installation".

3.Check harness between combination switch (spiral cable) and audio unit

1. Disconnect audio unit connector M43.
2. Check continuity between combination switch (spiral cable) connector m80 and audio unit connector m43.

3. Check continuity between combination switch (spiral cable) connector m80 and ground.

Is the inspection result normal? Yes >> replace audio unit. Refer to av-58, "removal and installation".

No >> repair or replace harness or connectors.