Pinpoint Test C: No Sound From One Or More Speakers (Not All Speakers) - Vehicles With Navigation
Information and Entertainment System
Pinpoint Test C: No Sound From One Or More Speakers (Not All Speakers) - Vehicles With Navigation
Normal Operation
The Audio Front Control Module (ACM) directs audio signals to the audio amplifier in the form of an AC voltage. The ACM (Audio Front Control Module) provides internal circuit protection for shorts to ground or shorts to voltage.
A short to ground or short to voltage in the circuitry to the audio amplifier may cause multiple speakers to lose sound due to the built-in overload protection feature of the ACM (Audio Front Control Module).
The speaker walk test can be used to isolate a concern with a particular speaker. This can reduce the diagnostic steps necessary to isolate the concern. To carry out the speaker walk test, refer to Audio Control Module (ACM) Self-Diagnostic Mode Audio Control Module (ACM) Self-Diagnostic Mode.
For vehicles with 6 speakers, each middle speaker is wired in series with the corresponding rear speaker. A concern in the wiring to either speaker causes both speakers to be inoperative.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Speaker
- Audio amplifier
- ACM (Audio Front Control Module)
PINPOINT TEST C : NO SOUND FROM ONE OR MORE SPEAKERS (NOT ALL SPEAKERS) - VEHICLES WITH NAVIGATION
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings.
C1 CHECK THE AUDIO SIGNALS TO THE SUSPECT SPEAKER
- Ignition OFF.
- Disconnect: Suspect Speaker.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the suspect speaker pin 1 and pin 2, harness side as follows:
Suspect Speaker Positive Meter Lead Negative Meter Lead LF door C523-1 VME07 (WH) C523-2 RME07 (WH/BN) RF door C612-1 VME10 (WH/VT) C612-2 RME10 (WH/OG) Left middle C3130-1 VME09 (WH/GN) C3130-2 VME79 (GY/VT) Right middle C813-1 VME12 (BN/WH) C813-2 VME78 (GN/VT) Left rear C484-1 VME79 (GY/VT) C484-2 RME09 (BN/YE) Right rear C485-1 VME78 (GN/VT) C485-2 RME12 (BN/BU)
Is a fluctuating AC voltage present?
Yes
INSTALL a new speaker for the suspect speaker. REFER to Speaker - Door Service and Repair. TEST the system for normal operation.
No
GO to C2.
C2 CHECK THE AUDIO SIGNALS TO THE AUDIO AMPLIFIER
- Ignition OFF.
- Disconnect: Audio Amplifier C2385A.
- Operate the audio system in radio tuner (AM/FM) mode.
- Measure the AC voltage between the audio amplifier pins for the suspect speaker, harness side as follows:
Suspect Speaker Positive Meter Lead Negative Meter Lead LF door C2385A-8 VME17 (GN) C2385A-4 RME17 (GY) RF door C2385A-6 VME18 (VT) C2385A-2 RME18 (YE) Left middle or left rear C2385A-7 VME60 (GN/BN) C2385A-3 RME60 (GY/BN) Right middle or right rear C2385A-5 VME61 (VT/BN) C2385A-1 RME61 (YE/BU)
Is a fluctuating AC voltage present?
Yes
GO to C5.
No
GO to C3.
C3 CHECK THE AUDIO CIRCUITS TO THE AUDIO AMPLIFIER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM (Audio Front Control Module) C240A.
- Ignition ON.
- Measure the voltage between the audio amplifier, harness side and ground as follows:
Suspect Speaker Positive Meter Lead Negative Meter Lead LF door C2385A-8 VME17 (GN) Ground C2385A-4 RME17 (GY) Ground RF door C2385A-6 VME18 (VT) Ground C2385A-2 RME18 (YE) Ground Left middle or left rear C2385A-7 VME60 (GN/BN) Ground C2385A-3 RME60 (GY/BN) Ground Right middle or right rear C2385A-5 VME61 (VT/BN) Ground C2385A-1 RME61 (YE/BU) Ground
Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to C4.
C4 CHECK THE AUDIO CIRCUITS TO THE AUDIO AMPLIFIER FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between the audio amplifier, harness side and the ACM (Audio Front Control Module), harness side; and between the audio amplifier, harness side and ground as follows:
Suspect Speaker Positive Meter Lead Negative Meter Lead Circuit LF door C2385A-8 C240A-8, then ground VME17 (GN) C2385A-4 C240A-21, then ground RME17 (GY) RF door C2385A-6 C240A-11, then ground VME18 (VT) C2385A-2 C240A-12, then ground RME18 (YE) Left middle or left rear C2385A-7 C240A-9, then ground VME60 (GN/BN) C2385A-3 C240A-22, then ground RME60 (GY/BN) Right middle or right rear C2385A-5 C240A-10, then ground VME61 (VT/BN) C2385A-1 C240A-23, then ground RME61 (YE/BU)
Is the resistance less than 5 ohms between the audio amplifier and the ACM (Audio Front Control Module), and greater than 10,000 ohms between the audio amplifier and ground?
Yes
GO to C7.
No
REPAIR the circuit in question. TEST the system for normal operation.
C5 CHECK THE CIRCUITS TO THE SUSPECT SPEAKER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Audio Amplifier C2358B.
- Ignition ON.
- Measure the voltage between the suspect speaker, harness side and ground as follows:
Suspect Speaker Positive Meter Lead Negative Meter Lead LF door C523-1 VME07 (WH) Ground C523-2 RME07 (WH/BN) Ground RF door C612-1 VME10 (WH/VT) Ground C612-2 RME10 (WH/OG) Ground Left middle C3130-1 VME09 (WH/GN) Ground C3130-2 VME79 (GY/VT) Ground Right middle C813-1 VME12 (BN/WH) Ground C813-2 VME78 (GN/VT) Ground Left rear C484-1 VME79 (GY/VT) Ground C484-2 RME09 (BN/YE) Ground Right rear C485-1 VME78 (GN/VT) Ground C485-2 RME12 (BN/BU) Ground
Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to C6.
C6 CHECK THE CIRCUITS TO THE SUSPECT SPEAKER FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between the audio amplifier (or speaker for 6 speaker configuration), harness side and the suspect speaker, harness side; and between the audio amplifier (or speaker for 6 speaker configuration), harness side and ground as follows:
Suspect Speaker Positive Meter Lead Negative Meter Lead Circuit LF door C2385B-13 C523-1, then ground VME07 (WH) C2385B-6 C523-2, then ground RME07 (WH/BN) RF door C2385B-11 C612-2, then ground VME10 (WH/VT) C2385B-4 C612-2, then ground RME10 (WH/OG) Left middle C2385B-12 C3130-1, then ground VME09 (WH/GN) C484-1 C3130-2, then ground VME79 (GY/VT) Right middle C2385B-10 C813-2, then ground VME78 (GN/VT) C485-1 C813-2, then ground RME12 (BN/BU) Left rear (4 speaker) C2385B-12 C484-1, then ground VME09 (WH/GN) C2385B-5 C484-2, then ground RME09 (BN/YE) Left rear (6 speaker) C3130-2 C484-1, then ground VME79 (GY/VT) C2385B-5 C484-2, then ground RME09 (BN/YE) Right rear (4 speaker) C2385B-10 C485-1, then ground VME12 (BN/WH) C2385B-2 C485-2, then ground RME12 (BN/BU) Right rear (6 speaker) C813-2 C485-1, then ground VME78 (GN/VT) C2385B-2 C485-2, then ground RME12 (BN/BU)
Is the resistance less than 5 ohms between the audio amplifier and the suspect speaker, and greater than 10,000 ohms between the audio amplifier and ground?
Yes
INSTALL a new audio amplifier. REFER to Audio Amplifier Service and Repair. TEST the system for normal operation.
No
REPAIR the circuit in question. TEST the system for normal operation.
C7 CHECK FOR CORRECT ACM (Audio Front Control Module) OPERATION
- Connect: All Disconnected Connectors.
- Disconnect all the ACM (Audio Front Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the ACM (Audio Front Control Module) connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes
INSTALL a new ACM (Audio Front Control Module). REFER to Audio Control Module (ACM) Audio Control Module (ACM). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.