Pinpoint Test X: DTC B1318 (Audio Control Module (ACM))

Information and Entertainment System

Pinpoint Tests

Pinpoint Test X: DTC B1318 (Audio Control Module (ACM))

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

Normal Operation
- DTC B1318 (Battery Voltage Low) - set by the Audio Control Module (ACM) as a continuous or on-demand DTC if the ACM detects low battery voltage below 10 volts for greater than 10 seconds on circuit SBP11 (BU/RD).

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- High circuit resistance
- ACM



PINPOINT TEST X: DTC B1318 (ACM)

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. Refer to Battery.

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X1 RECHECK THE ACM DTCs


- Clear the ACM DTCs.
- Ignition OFF.
- Ignition ON.
- Wait 10 seconds.
- Repeat the ACM self-test.
- Is DTC B1318 still present?

Yes
GO to X2.

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

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X2 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 X3.

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X3 CHECK THE BATTERY CONDITION AND STATE OF CHARGE


- Check the battery condition and verify that the battery is fully charged. Refer to Battery.
- Is the battery OK and fully charged?

Yes
GO to X4.

No
REFER to Battery.

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X4 CHECK THE ACM VOLTAGE SUPPLY


- Ignition OFF.
- Measure and record the voltage at the battery.
- Disconnect: ACM C240a or C290a.
- Ignition ON.
- Measure the voltage between the ACM C290a-1 (or C240a-1), circuit SBP11 (BU/RD), harness side and ground.




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

Yes
GO to X5.

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

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X5 CHECK THE ACM GROUND CIRCUIT


- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the ACM C290a-13 (or C240a-13), circuit GD114 (BK/BU), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
GO to X6.

No
REPAIR the circuit for high resistance. TEST the system for normal operation.

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X6 CHECK FOR CORRECT ACM OPERATION


- Disconnect the ACM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the ACM connector and make sure it seats correctly.
- Is the concern still present?

Yes
INSTALL a new ACM. REFER to Audio Control Module (ACM) - Fusion, Milan Audio Control Module (ACM) - Fusion, Milan. 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.

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