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For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2007 🢒 Ascender - 2WD 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Speakers Inoperative - One or More

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Amplifier B+

2

2

--

--

Antenna 14V Switched Supply Voltage

2

2

--

--

Left Front Speaker Output (+)/Left Front Low Level Audio Signal (+)

B1025 02*

1

B1025 01*

--

Left Front Speaker Output (-)/Left Front Low Level Audio Signal (-)

B1025 02*

1

B1025 01*

--

Right Front Speaker Output (+)/Right Front Low Level Audio Signal (+)

B1035 02*

1

B1035 01*

--

Right Front Speaker Output (-)/Right Front Low Level Audio Signal (-)

B1035 02*

1

B1035 01*

--

Left Rear Speaker Output (+)/Left Rear Low Level Audio Signal (+)

B1045 02*

1

B1045 01*

--

Left Rear Speaker Output (-)/Left Rear Low Level Audio Signal (-)

B1045 02*

1

B1045 01*

--

Right Rear Speaker Output (+)/Right Rear Low Level Audio Signal (+)

B1055 02*

1

B1055 01*

--

Right Rear Speaker Output (-)/Right Rear Low Level Audio Signal (-)

B1055 02*

1

B1055 01*

--

Amplifier Ground

--

2

--

--

1. No or reduced sound from speaker

2. Amplifier inoperative/no sound from speakers

* Noticeable audio distortion possible

Circuit/System Description

Each of the audio output channel circuits (+) and (-), at the radio and at the amplifier (if equipped) have a DC bias voltage that is one half of the battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5V DC. The audio being played on the system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage is what causes the speaker cone to move and produce sound. This voltage will vary depending on what type of audio is being listened to, talk or music, and type of music, as well as the volume setting of the system. Low volume and talk settings will measure around 1V AC and less, where constant music may measure 3V AC and slightly higher.

Diagnostic Aids
    • Improper speaker mounting or loose trim may cause an audible buzz or distortion. Inspect the appropriate speaker and the surrounding interior trim for proper and secure mounting. If the speaker or surrounding interior trim is found to be loose or improperly secured, correctly secure the item.
    • When equipped with an amplifier, it is possible for some individual circuit faults to affect more than one speakers operation. Perform diagnostic tests in the sequence listed to avoid misdiagnosis.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Entertainment/Communication Connector End Views

Description and Operation

Radio/Audio System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Verification

Without Amplifier

Radio ON, verify clear audio is heard from each audio speaker.

⇒If audio is inoperative from all speakers, replace the radio.
⇒If audio is inoperative from one or more, but not all, speakers or the audio emitted from the speakers is not clear, refer to Speaker Circuit Malfunction - without Amplifier.

With Amplifier

Radio ON, verify clear audio is heard from each audio speaker.

⇒If audio is inoperative from all speakers, refer to Amplifier Circuit Malfunction.
⇒If audio is inoperative from one or more, but not all, speakers or the audio emitted from the speakers is not clear, refer to Speaker Circuit Malfunction - with Amplifier.

Circuit/System Testing

Note: If equipped with rear seat audio (RSA), the RSA must be turned off to perform proper speaker testing.

Speaker Circuit Malfunction - without Amplifier

  1. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground.
    2. ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  2. Test for 5.0-7.5 volts between the signal circuit terminal B and ground.
    3. ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. If all circuits test normal, replace the speaker.

Speaker Circuit Malfunction - without Amplifier with RSA -- Front Speaker Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate speaker.
  2. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground.
    3. ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. Test for 5.0-7.5 volts between the signal circuit terminal B and ground.
    4. ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  4. If all circuits test normal, replace the speaker.

Without Amplifier with RSA -- Rear Speaker Testing

  1. Ignition OFF, disconnect the CJ2 harness connector at the HVAC Control Module.
  2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    3. • Left rear low level audio signal (+) - terminal B3
    • Left rear low level audio signal (-) - terminal B7
    • Right rear low level audio signal (+) - terminal B4
    • Right rear low level audio signal (-) - terminal B8
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  3. Ignition OFF, disconnect the harness connector at the appropriate speaker.
  4. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground.
    5. ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HVAC Control Module.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC Control Module.
  5. Test for 5.0-7.5 volts between the signal circuit terminal B and ground.
    6. ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the HVAC Control Module.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC Control Module.
  6. If all circuits test normal, replace the speaker.

Amplifier Circuit Malfunction

  1. Ignition OFF, disconnect the C2 harness connector at the amplifier.
  2. Test for less than 10 ohms between the ground circuit terminal A and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Test for B+ between the battery voltage circuit terminal H and ground.
    4. ⇒If less than the specified value, test the circuit for a short to ground or an open/high resistance.
  4. Disconnect the C1 harness connector at the amplifier.
  5. Radio ON, test for B+ between the signal circuit terminal B11 and ground.
    6. ⇒If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  6. If all circuits test normal, replace the amplifier.

Speaker Circuit Malfunction - with Amplifier - Front and Rear Speaker Testing

  1. Ignition OFF, disconnect the C1 connector at the amplifier.
  2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    3. • Left front low level audio signal (+) - terminal B10 C1
    • Left front low level audio signal (-) - terminal B9 C1
    • Right front low level audio signal (+) - terminal B8 C1
    • Right front low level audio signal (-) - terminal B7 C1
    • Left rear low level audio signal (+) - terminal B6 C1
    • Left rear low level audio signal (-) - terminal B5 C1
    • Right rear low level audio signal (+) - terminal B4 C1
    • Right rear low level audio signal (-) - terminal B3 C1
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. Ignition OFF, disconnect the C1 and C2 harness connectors at the amplifier.
  4. Ignition ON, test for less than 1 volt between each of the signal circuit terminals listed below and ground.
    5. • Left front speaker output (-) - terminal A6 C1
    • Left front speaker output (+) - terminal A5 C1
    • Right front speaker output (-) - terminal A8 C1
    • Right front speaker output (+) - terminal A7 C1
    • Left rear speaker output (-) - terminal G C2
    • Left rear speaker output (+) - terminal B C2
    • Right rear speaker output (-) - terminal F C2
    • Right rear speaker output (+) - terminal C C2
    ⇒If greater than the specified range, test the signal circuit for a short to voltage.
  5. Ignition OFF, test for infinite resistance between each of the signal circuit terminals listed below and ground.
    6. • Left front speaker output (-) - terminal A6 C1
    • Left front speaker output (+) - terminal A5 C1
    • Right front speaker output (-) - terminal A8 C1
    • Right front speaker output (+) - terminal A7 C1
    • Left rear speaker output (-) - terminal G C2
    • Left rear speaker output (+) - terminal B C2
    • Right rear speaker output (-) - terminal F C2
    • Right rear speaker output (+) - terminal C C2
    ⇒If less than the specified value, test the signal circuit for a short to ground.
  6. Ignition OFF, reconnect all harness connectors at the amplifier. Disconnect the harness connector at the appropriate speaker.
  7. Radio ON, test for 5.0-7.5 volts each of the signal circuit terminals listed below and ground.
    8. • Front door speakers - terminal A and B
    • Front IP speakers - terminal A and B
    • Rear door speakers- terminal A and B
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the amplifier.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
  8. If all circuits test normal, replace the speaker.

With Amplifier and RSA - Front and Rear Speaker Testing

  1. Ignition OFF, disconnect the C1 harness connector at the amplifier.
  2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    3. • Left front low level audio signal (+) - terminal B10
    • Left front low level audio signal (-) terminal B9
    • Right front low level audio signal (+) - terminal B8
    • Right front low level audio signal (-) - terminal B7
    • Left rear low level audio signal (+) - terminal B6
    • Left rear low level audio signal (-) - terminal B5
    • Right rear low level audio signal (+) - terminal B4
    • Right rear low level audio signal (-) - terminal B3
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. Ignition OFF, reconnect the C1 harness connector at the amplifier.
  4. Disconnect the CJ2 harness connector at the HVAC Control Module.
  5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    6. • Left rear low level audio signal (+) - terminal B3
    • Left rear low level audio signal (-) - terminal B7
    • Right rear low level audio signal (+) - terminal B4
    • Right rear low level audio signal (-) - terminal B8
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  6. Ignition OFF, reconnect the CJ2 harness connector at the HVAC Control Module.
  7. Disconnect the C1 and C2 harness connectors at the amplifier.
  8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    9. • Left rear low level audio signal (+) - terminal B6 C1
    • Left rear low level audio signal (-) - terminal B5 C1
    • Right rear low level audio signal (+) - terminal B4 C1
    • Right rear low level audio signal (-) - terminal B3 C1
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear seat audio (RSA) module.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
  9. Ignition ON, test for less than 1 volt between each of the signal circuit terminals listed below and ground.
    10. • Left front speaker output (+) - terminal A5 C1
    • Left front speaker output (-) - terminal A6 C1
    • Right front speaker output (+) - terminal A7C1
    • Right front speaker output (-) - terminal A8 C1
    • Left rear speaker output (+) - terminal B C2
    • Left rear speaker output (-) - terminal G C2
    • Right rear speaker output (+) - terminal C C2
    • Right rear speaker output (-) - terminal F C2
    ⇒If greater than the specified range, test the signal circuit for a short to voltage.
  10. Ignition OFF, test for infinite resistance between each of the signal circuit terminals listed below and ground.
    11. • Left front speaker output (+) - terminal A5 C1
    • Left front speaker output (-) - terminal A6 C1
    • Right front speaker output (+) - terminal A7C1
    • Right front speaker output (-) - terminal A8 C1
    • Left rear speaker output (+) - terminal B C2
    • Left rear speaker output (-) - terminal G C2
    • Right rear speaker output (+) - terminal C C2
    • Right rear speaker output (-) - terminal F C2
    ⇒If less than the specified range, test the signal circuit for a short to ground.
  11. Ignition OFF, reconnect all harness connectors at the amplifier. Disconnect the harness connector at the appropriate speaker.
  12. Radio ON, test for 5.0-7.5 volts each of the signal circuit terminals listed below and ground.
    13. • Front door speakers - terminal A and B
    • Front IP speakers - terminal A and B
    • Rear door speakers- terminal A and B
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the amplifier.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
  13. If all circuits test normal, replace the speaker.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Speaker Replacement Reference
    •  Control Module References for Amplifier or Radio replacement