Pinpoint Test B: No Sound From One Or More Speakers (Not All Speakers) - Vehicles Without Navigation
Information and Entertainment System
Pinpoint Test B: No Sound From One Or More Speakers (Not All Speakers) - Vehicles Without Navigation
NOTE: In Normal Operation, the terms Audio Front Control Module (ACM) and in-dash computer are synonymous.
Normal Operation
The ACM (Audio Front Control Module) directs audio signals to the speakers 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 one of the speakers may cause multiple speakers to lose sound due to the built-in overload protection feature of the ACM (Audio Front Control Module). In this case, a speaker fault DTC sets, and this pinpoint test should be followed to isolate the damaged circuit.
It should also be noted that when the ACM (Audio Front Control Module) activates the built-in overload protection, DTC B1342 may also be set. The circuit failure must be repaired before DTC B1342 can be cleared.
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
- ACM (Audio Front Control Module) (vehicles without Ford Work Solutions(TM))
- In-dash computer (vehicles with Ford Work Solutions(TM))
PINPOINT TEST B : NO SOUND FROM ONE OR MORE SPEAKERS (NOT ALL SPEAKERS) - VEHICLES WITHOUT NAVIGATION
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
B1 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. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to B2.
B2 CHECK THE CIRCUITS TO THE SUSPECT SPEAKER FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: ACM (Audio Front Control Module) C240A (In-Dash Computer C2408A).
- 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 C484-1VME79 (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. CLEAR any DTCs present. TEST the system for normal operation.
No
GO to B3.
B3 CHECK THE CIRCUITS TO THE SUSPECT SPEAKER FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between the ACM (Audio Front Control Module) (or speaker for 6-speaker configuration) (in-dash computer), harness side and the suspect speaker, harness side; and between the ACM (Audio Front Control Module) (or speaker for 6-speaker configuration) (in-dash computer), harness side and ground as follows:
Suspect Speaker Positive Meter Lead Negative Meter Lead Circuit LF door C240A-8 (C2408A-8) C523-1, then ground VME07 (WH) C240A-21 (C2408A-21) C523-2, then ground RME07 (WH/BN) RF door C240A-11 (C2408A-11) C612-1, then ground VME10 (WH/VT) C240A-12 (C2408A-12) C612-2, then ground RME10 (WH/OG) Left middle C240A-9 (C2408A-9) C3130-1, then ground VME09 (WH/GN) C484-1 C3130-2, then ground VME79 (GY/VT) Right middle C240A-10 (C2408A-10) C813-2, then ground VME12 (BN/WH) C485-1 C813-2, then ground VME78 (GN/VT) Left rear (4 speaker) C240A-9 (C2408A-9) C484-1, then ground VME09 (WH/GN) C240A-22(C2408A-22) C484-2, then ground RME09 (BN/YE) Left rear (6 speaker) C3130-2 C484-1, then ground VME79 (GY/VT) C240A-22 (C2408A-22) C484-2, then ground RME09 (BN/YE) RR door (4 speaker) C240A-10 (C2408A-10) C485-1, then ground VME12 (BN/WH) C240A-23 (C2408A-23) C485-2, then ground RME12 (BN/BU) RR door (6 speaker) C813-2 C485-1, then ground VME78 (GN/VT) C240A-23 (C2408A-23) C485-2, then ground RME12 (BN/BU)
Is the resistance less than 5 ohms between the ACM (Audio Front Control Module) (in-dash computer) and the suspect speaker, and greater than 10,000 ohms between the ACM (Audio Front Control Module) (in-dash computer) and ground?
Yes
GO to B4.
No
REPAIR the circuit in question. CLEAR any DTCs present. TEST the system for normal operation.
B4 CHECK FOR CORRECT ACM (Audio Front Control Module) (IN-DASH COMPUTER) OPERATION
- Connect: All Disconnected Connectors.
- Disconnect all the ACM (Audio Front Control Module) (in-dash computer) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the ACM (Audio Front Control Module) (in-dash computer) 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) (in-dash computer). REFER to Audio Control Module (ACM) Audio Control Module (ACM) or In-Dash Computer In-Dash Computer. 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.