Accessories and Optional Equipment

Information and Entertainment System

Pinpoint Test T: DTC B1318 (Late Build)

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

Normal Operation

- DTC B1318 (Battery Voltage Low)- set by the ACM (Audio Front Control Module) as a continuous or on-demand DTC when the supply voltage is below 10 volts for more than 10 seconds with the ignition in the RUN or ACC position.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- High circuit resistance

- ACM (Audio Front Control Module)

PINPOINT TEST T : DTC B1318 (LATE BUILD)

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.

T1 RECHECK THE ACM (Audio Front Control Module) DTCs

- Clear the ACM (Audio Front Control Module) DTCs.

- Ignition OFF.

- Ignition ON.

- Wait 10 seconds.

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

Is DTC B1318 still present?

Yes
GO to T2.

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

T2 CHECK FOR CHARGING SYSTEM DTCs IN THE PCM

- Retrieve the continuous memory DTCs from all modules.

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

Yes
REFER to Charging System.

No
GO to T3.

T3 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 T4.

No
REFER to Charging System.

T4 CHECK THE ACM (Audio Front Control Module) VOLTAGE SUPPLY

- Ignition OFF.

- Measure and record the voltage at the battery.

- Disconnect: ACM (Audio Front Control Module) C290A.

- Ignition ON.

- Measure the voltage between the ACM (Audio Front Control Module), harness side and ground.

Positive Meter Lead Negative Meter Lead Circuit C290A-1 Ground 29-MD15 (OG/BK) C290A-2 Ground 75-MD15 (YE/GN)






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

Yes
GO to T5.

No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

T5 CHECK THE ACM (Audio Front Control Module) GROUND CIRCUIT FOR CONTINUITY

- Ignition OFF.

- Disconnect: Negative Battery Cable.

- Measure the resistance between the ACM (Audio Front Control Module), harness side and ground

Positive Meter Lead Negative Meter Lead Circuit C290A-13 Ground 91-MD15 (BK/GN) C290A-4 Ground 91-LK34 (BK/GN)






Are the resistances less than 3 ohms?

Yes
GO to T6.

No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

T6 CHECK FOR CORRECT ACM (Audio Front Control Module) OPERATION

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

- Check for:
- corrosion

- damaged pins

- pushed-out pins


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

Is the concern still present?

Yes
INSTALL a new ACM (Audio Front Control Module). REFER to 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.