HandsFreeLink System Symptom Troubleshooting - The HFL prompts or incoming call cannot be heard or are weak (HFL information display is normal)
The HFL prompts or incoming call cannot be heard or are weak (HFL information display is normal)
NOTE:
Check the vehicle 12 volt battery condition first.
The HFL volume affects both the prompts and the incoming calls. For example, if you turn down the volume during an incoming call, you also turn down the volume on the HFL prompts. The customer may turn down the volume because a call is loud, not realizing they also turned down the HFL prompt volume.
Check the connectors for poor connections or loose terminals.
1.
Determine possible failure area (audio system, HFL system):

Determine possible failure area (audio system, HFL system)
?1.
Turn the vehicle to the ON mode.

?2.
Check that the audio system is operating normally, from different audio sources (AM/FM and CD) and the speaker sound levels are normal.

Does the audio system work normally and is the audio output from the speaker normal when playing various audio sources?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
2.
Problem verification 1:

Problem verification 1
?1.
Compare the voice prompts to a known-good vehicle of the same year/model/trim using the same volume settings.

Are the voice prompt volume and the clarity the same as the customer's vehicle?

     
YES
     
     
     
Intermittent failure, the system is OK at this time.?
     
NO
     
     
     
The failure is duplicated, go to step 3.
3.
Problem verification 2:

Problem verification 2
?1.
Do the HFL Self-Diagnostic Function.

Is the HFL prompt played?

     
YES: ‘‘The HFT is OK.’’ is played
     
     
     
Intermittent failure, the system is OK at this time. If possible, have the customer demonstrate the issue.?
     
YES: ‘‘The HFT is NG.’’ is played
     
     
     
     
NO
     
     
     
The failure is duplicated, go to step 4.
4.
Shorted wire check (TELEM SIG+ line, TELEM SIG? line):

Shorted wire check (TELEM SIG+ line, TELEM SIG? line)
?1.
Turn the vehicle to the OFF (LOCK) mode.

?2.
Disconnect the following connectors.
Audio unit connector B (20P)
HandsFreeLink control unit 32P connector

?3.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Audio unit connector B (20P): disconnected
 
HandsFreeLink control unit 32P connector: disconnected
Test point 1
HandsFreeLink control unit 32P connector No. 4
Test point 2
Body ground

Test point 1
HandsFreeLink control unit 32P connector No. 20
Test point 2
Body ground

Is there continuity?

     
YES
     
     
     
There is a short to body ground in the wire(s) between the audio unit and the HandsFreeLink control unit. Replace the affected shielded harness.?
     
NO
     
     
     
The TELEM SIG+ and the TELEM SIG? wires are not shorted to ground. Go to step 5.
5.
Shorted wire check (TELEM SIG+ line to TELEM SIG? line):

Shorted wire check (TELEM SIG+ line to TELEM SIG? line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Audio unit connector B (20P): disconnected
 
HandsFreeLink control unit 32P connector: disconnected
Test point 1
HandsFreeLink control unit 32P connector No. 4
Test point 2
HandsFreeLink control unit 32P connector No. 20

Is there continuity?

     
YES
     
     
     
There is a short in the wires between the audio unit and the HandsFreeLink control unit. Replace the affected shielded harness.?
     
NO
     
     
     
The TELEM SIG+ and the TELEM SIG? wires are not shorted. Go to step 6.
6.
Shorted wire check (SH TELEM SIG line to another lines):

Shorted wire check (SH TELEM SIG line to another lines)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Audio unit connector B (20P): disconnected
 
HandsFreeLink control unit 32P connector: disconnected
Test point 1
HandsFreeLink control unit 32P connector No. 19
Test point 2
HandsFreeLink control unit 32P connector No. 4


Is there continuity?

     
YES
     
     
     
There is a short in the wires between the audio unit and the HandsFreeLink control unit. Replace the affected shielded harness.?
     
NO
     
     
     
The SH TELEM SIG wire is OK. Go to step 7.
7.
Open wire check (TELEM SIG+ line, TELEM SIG? line):

Open wire check (TELEM SIG+ line, TELEM SIG? line)
?1.
Check for continuity between test points 1 and 2.
Test condition
Vehicle OFF (LOCK) mode
 
Audio unit connector B (20P): disconnected
 
HandsFreeLink control unit 32P connector: disconnected
Test point 1
Audio unit connector B (20P) No. 12
Test point 2
HandsFreeLink control unit 32P connector No. 4


Is there continuity?

     
YES
     
     
     
The TELEM SIG+ and the TELEM SIG? wires are OK. Go to step 8.
     
NO
     
     
     
There is an open in the wire(s) between the audio unit and the HandsFreeLink control unit. Replace the affected shielded harness.?
8.
HandsFreeLink control unit check (substitution):

HandsFreeLink control unit check (substitution)
?1.
Substitute a known-good HandsFreeLink control unit.

?2.
Reconnect all the connectors, and recheck.

Does the symptom go away?

     
YES
     
     
     
     
NO