Pinpoint Test AO: DTC B1318 Or DTC U3003:16 (Audio Control Module (ACM) )

Information and Entertainment System

Pinpoint Test AO: DTC B1318 Or DTC U3003:16 (Audio Control Module (ACM))

Refer to Wiring Diagram Set 130, Audio System/Navigation for schematic and connector information. [1][2]Diagrams By Number

Normal Operation

- DTC B1318 (Battery Voltage Low)- set by the non-navigation (Fusion) Audio Control Module (ACM) as a continuous or on-demand DTC when the supply voltage falls below 10 volts for at least 10 seconds during normal operation.

- DTC U3003:16 (Battery Voltage: Circuit Voltage Below Threshold)- set by the non-navigation (MKZ) or navigation (all) ACM (Audio Control Module) as a continuous or on-demand DTC when the supply voltage falls below 10 volts for at least 10 seconds during normal operation, or for greater than 250 milliseconds during the self-test.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- High circuit resistance

- ACM (Audio Control Module)

PINPOINT TEST AO : DTC B1318 Or DTC U3003:16 (ACM (Audio Control Module))

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.

AO1 RECHECK THE ACM (Audio Control Module) DTCs

- Clear the ACM (Audio Control Module) DTCs.

- Ignition OFF.

- Ignition ON.

- Wait 10 seconds.

- Repeat the ACM (Audio Control Module) self-test.

Is DTC B1318 or DTC U3003:16 still present?

Yes
GO to AO2.

No
The system is operating correctly at this time. The DTC may have set due to a previous low battery voltage condition.

AO2 CHECK FOR CHARGING SYSTEM DTCs IN THE PCM

- Retrieve the continuous memory DTCs from all modules.

Is DTC P0620, P0622, P0625, P0626, or P065B set in the PCM?

Yes
REFER to Charging System.

No
GO to AO3.

AO3 CHECK THE BATTERY CONDITION AND STATE OF CHARGE

- Check the battery condition and verify that the battery is fully charged.

Is the battery OK and fully charged?

Yes
GO to AO4.

No
REFER to Battery.

AO4 CHECK THE ACM (Audio Control Module) VOLTAGE SUPPLY

- Ignition OFF.

- Measure and record the voltage at the battery.

- Disconnect: ACM (Audio Control Module) C240A.

- Ignition ON.

- Measure the voltage between the ACM (Audio Control Module) C240A-1, circuit SBP39 (WH/RD), harness side and ground.





Is the voltage within 0.2 volt of the recorded battery voltage?

Yes
GO to AO5.

No
REPAIR the circuit for high resistance. CLEAR the DTCs. REPEAT the self-test.

AO5 CHECK THE ACM (Audio Control Module) GROUND CIRCUIT FOR CONTINUITY

- Ignition OFF.

- Disconnect: Negative Battery Cable.

- Measure the resistance between the ACM (Audio Control Module) C240A-13, circuit GD114 (BK/BU), harness side and ground.





Is the resistance less than 5 ohms?

Yes
GO to AO6.

No
REPAIR the circuit for high resistance. CLEAR the DTCs. REPEAT the self-test.

AO6 CHECK FOR CORRECT ACM (Audio Control Module) OPERATION

- Disconnect all the ACM (Audio Control Module) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the ACM (Audio Control Module) connectors and make sure they seat correctly.

Is the concern still present?

Yes
INSTALL a new ACM (Audio Control Module). REFER to Audio Control Module (ACM) - Fusion or Audio Control Module (ACM) - MKZ . 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.