Component Tests and General Diagnostics
Sound Quality DiagnosisSpecial Tools Required
Audio diagnostic CD 07AAZ-SDBA100
Use the following tests to check sound quality.
NOTE: Before beginning the following tests, write down the client's Bass, Treble, Fader, and Balance settings; then set them to their center positions for the testing.
Left/Right Channel ID
Do this test to confirm proper channel routing.
1. Insert audio diagnostic CD (T/N 07AAZ-SDBA100) into the CD player.
2. Play track No. 1 (left, both, right channel ID) at a normal, or slightly higher than normal, volume level.
3. The voice should be a audible only from the channel or channels when indicated.
- If the channel ID is correct for each side, go to Phase Test.
- If the channel ID is not correct, check for:
- Shorted speaker wire
- Faulty amplifier
- Faulty audio unit
Special Tools Required
Audio diagnostic CD 07AAZ-SDBA100
Use the following tests to check sound quality.
NOTE: Before beginning the following tests, write down the client's Bass, Treble, Fader, and Balance settings; then set them to their center positions for the testing.
Phase Test
Do this test to confirm proper speaker phasing.
1. Insert audio diagnostic CD (T/N 07AAZ-SDBA100) into the CD player.
2. Play track No, 2 (phase) at a normal, or slightly higher than normal, volume level.
3. The voice should sound centered and focused when it is in-phase
4. The voice should sound diffused, and have "less bass" when it is out-of -phase.
- If the voice changes from in-phase to out of phase as indicated by the prompt, the phasing is correct. Go to Electrical Noise Test.
- If the voice always sounds out of phase, phasing is not correct. Check for:
- Crossed speaker wires
- Faulty amplifier
- Faulty audio unit
Special Tools Required
Audio diagnostic CD 07AAZ-SDBA100
Use the following tests to check sound quality.
NOTE: Before beginning the following tests, write down the client's Bass, Treble, Fader, and Balance settings; then set them to their center positions for this testing.
Electrical Noise Test
Do this test to check for.electrical noise being induced into the audio system.
NOTE: Electrical noise may be caused by outside sources that cannot be prevented by the audio system. Make sure you remove any cell phones and/or turn off any aftermarket devices before beginning this test.
1. Insert audio diagnostic CD (T/N 07AAZ-SDBA100) into the CD player.
2. Play track No. 4 (digital zero) at a normal, or slightly higher than normal, volume level.
3. Operate any electrical devices that cause noise from the audio system, including starting the engine.
4. Play track No. 5 (near digital zero) at a normal, or slightly higher than normal, volume level.
5. Operate any electrical devices that cause noise from the audio system, including starting the engine.
6. Play track No. 6 (SNR) at a normal, or slightly higher than normal, volume level.
7. Operate any electrical devices that cause noise from the audio system, including starting the engine.
- If no abnormal noise is heard, go to Individual Speaker Test.
- If the noise is present only during the SNR track, replace the audio unit.
- If the noise is heard during the digital zero or near digital zero track, check for:
- Poor ground for the audio unit, amplifier, engine or battery cable.
- Pinched or shorted speaker or amplifier wire.
- Faulty amplifier
- Faulty audio unit
- Other faulty components causing excessive electrical noise (ignition coils, alternator, door lock actuators, etc.). Disconnect any suspect components, and then replay the tracks that were originally noisy. If the noise is gone, check the component's circuit and the component.
Special Tools Required
Audio diagnostic CD 07AAZ-SDBA100
Use the following tests to check sound quality.
NOTE: Before beginning the following tests, write down the client's Bass, Treble Fader, and Balance settings; then set them to their center positions for the testing.
Individual Speaker Test
Do this test to identify a faulty speaker.
1. Insert audio diagnostic CD (T/N 07AAZ-SDBA100) into the CD player.
2. Play track No. 30 (steady 300 Hz tone) at a normal, or slightly higher than normal, volume level.
3. Listen to each speaker for poor sound compared to the other channels. Use the audio unit's fader and balance settings to help isolate the channel with the problem.
- If the sound quality produced by a specific speaker is poor, substitute it with a know-good speaker. If the poor sound quality continues, go to the Sound Balance Test.
- If the sound quality is OK, go to the Sound Balance Test.
Special Tools Required
Audio diagnostic CD 07AAZ-SDBA100
Use the following tests to check sound quality.
NOTE: Before beginning the following tests, write down the client's Bass, Treble, Fader, and Balance settings; then set them to their center positions for the testing.
Sound Balance Test
Perform this test to identify a faulty channel or speaker.
1. Insert audio diagnostic CD (T/N 07AAZ-SDBA100) into the CD player.
2. Confirm the bass and treble are set to the center positions.
3. Play track No. 3 (pink noise) at a normal, or slightly higher than normal, volume level.
4. A "static" type sound should be heard through all speakers.
5. Insert audio diagnostic CD (T/N 07AAZ-SDBA100) into the CD player of a known-good vehicle.
6. Set the bass and treble to the center position.
7. Play track No. 3 (pink noise) at the same level as was played in step 3.
8. Compare the sounds made by the two vehicles.
- If the noise is very similar. Go to Frequency Sweep.
- If the sound does not have as much bass, check the subwoofer and circuit.
- If the sound does not have enough "hiss", check the tweeters and their circuits.
Special Tools Required
Audio diagnostic CD 07AAZ-SDBA100
Use the following tests to check sound quality.
NOTE: Before beginning the following tests, write down the client's Bass, Treble, Fader, and Balance settings; then set them to their center positions for the testing.
Frequency Sweep
Do this test to find rattles or reverberation that may cause a perception of poor sound quality.
1. Insert audio diagnostic CD (T/N 07AAZ-SDBA100) into the CD player.
2. Play track No. 13 (sweep from 500 Hz to 35 Hz) at a normal, or slightly higher than normal, volume level.
3. Listen to each speaker for poor sound quality or reverberations caused by specific frequencies. Use the voice-over to estimate the frequency that causes the vibration. Use the audio unit's fader and balance settings to help isolate the channel with the problem.
- If vibrations or poor sound quality is heard, go to step 4.
- If no vibration or poor sound quality is heard, go to Sound Judging.
4. Choose the appropriate track from No. 14 to 25 (small range frequency sweep) or 26 to 53 (single frequencies) to recreate the frequency that caused the poor sound quality or vibration witnessed in step 3; this aids in diagnosis of the cause.
NOTE: When you get to the track that recreates the problem, select the repeat function on the audio unit; this will help you isolate the cause.
5. Replace or insulate the source of the vibration or, if the speaker is the source of the poor sound quality, replace it.
Special Tools Required
Audio diagnostic CD 07AAZ-SDBA100
Use the following tests to check sound quality.
NOTE: Before beginning the following tests, write down the client's Bass, Treble, Fader, and Balance settings; then set them to their center positions for the testing.
Sound Judging
Do this test to compare overall sound quality, imaging, and dynamics between the problem vehicle and a known-good vehicle. Only use a vehicle of the same model and trim level for this test.
1. In the problem vehicle, set the Bass, Treble, Fader, and Balance settings to the customer's normal settings that were written down before beginning testing.
2. Insert audio diagnostic CD (T/N 07AAZ-SDBA100) into the CD player.
3. Play tracks No. 7 to 12 (Sound quality, midband, dynamics, and imaging demonstration tracks) at a normal, or slightly higher than normal, volume level. Write down the volume setting being used.
4. Listen to are areas of the track that stand out as being either real clear or poorer than other areas of the track.
5. In a know-good vehicle, insert audio diagnostic CD (T/N 07AAZ-SDBA100) into the CD player.
6. Play the same tracks at the same volume level and the same Bass, Treble, Balance, and Fader settings as used in step 3 in the client's vehicle.
7. Listen to the same areas of the track that stood out as being either real clear or poorer than other areas of the track.
8. Compare the problem vehicle's sound quality results to the known-good vehicle's results.
- If the sound quality in the problem vehicle is comparable to the sound quality in the known-good vehicle, then the problem vehicle is operating as designed.
- If the sound quality is not comparable, check these items in order:
- Loose or improperly installed speakers or other hardware that may become excited by the vibrations generated by the speakers
- Poor power or ground to the stereo amplifier
- Damaged speaker(s)
- Faulty amplifier
- Faulty audio unit
Special Tools Required
Audio diagnostic CD 07AAZ-SDBA100
Use the following tests to check sound quality.
NOTE: Before beginning the following tests, write down the client's Bass, Treble Fader, and Balance settings; then set them to their center positions for the testing.
Seek Stop Test
Do this test to check the performance of the audio unit's AM and FM reception. Refer to Symptom Troubleshooting: Audio Sound is Weak or Distorted, or No Sound is Heard From Speakers (Display is Normal) before continuing with this test. Audio System Sound Is Weak or Distorted, or No Sound Is Heard From Speakers (Display Is Normal)
NOTE:
- Window tint, aftermarket theft-recovery devices and other aftermarket accessories may reduce radio reception.
- Changes in cloud cover and other atmospheric conditions will affect the ability of the audio unit to receiver radio signals.
1. Park the problem vehicle in an open area away from buildings or other obstructions.
2. Park a known-good vehicle (same year, model, and trim level) next to the problem vehicle, facing the same direction.
3. Start the engine in the problem vehicle, and turn on the radio.
4. Set the FM receiver to 87.7 MHz.
5. Press the "Seek +" button, and record the first station that the audio unit locks on to.
6. Press the "Seek +" button repeatedly, and write down each station that the audio unit locks onto until the station recorded in step 5 is reached again.
7. Set the AM receiver to 530 kHz.
8. Press the "Seek +" button, and record the first station that the audio unit locks on to.
9. Press the "Seek +" button repeatedly, and write down each station that the audio unit locks onto until the station recorded in step 8 is reached again.
10. Turn the ignition switch OFF.
11. Start the engine in the known-good vehicle, and then perform step 4 thru 10 on the known-good vehicle.
12. Compare the number of stations received in step 6 and 9 in the client's vehicle with the number of stations received in the known-good vehicle.
- If the number of stations received is the same, or within 10 %, the audio unit's tuner performance is OK. The problem may be atmospheric conditions, multi-path interference, or other obstructions to the radio signal.
- If the client's vehicle receives fewer stations by at least 10 %, go to step 2 of Poor Radio Reception or Interference. Poor AM/FM Radio Reception or Interference