Pinpoint Test AC: DTC B1318
Handles, Locks, Latches and Entry Systems
Pinpoint Test AC: DTC B1318
Refer to Wiring Diagram Set 123 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Memory Seats for schematic and connector information. Diagrams By Number
Normal Operation
The Driver Door Module (DDM) monitors the voltage from the battery to determine if it goes above or below specific thresholds.
- DTC B1318 (Battery Voltage Low) - a continuous memory or on-demand DTC that sets when the DDM detects battery voltage below 10 volts on circuit SBP12.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- High circuit resistance
- DDM
PINPOINT TEST AC: DTC B1318
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, Mounting and Cables Battery Disconnect.
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AC1 RECHECK THE DDM DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DDM Self-Test.
- Clear the DTCs. Repeat the DDM self-test.
- Is DTC B1318 still present?
Yes
GO to AC2.
No
The system is operating normally at this time. The DTC may have been set previously during battery charging or while jump starting the vehicle.
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AC2 CHECK FOR CHARGING SYSTEM DTCs IN THE PCM
- Enter the following diagnostic mode on the scan tool: PCM Self-Test.
- Retrieve the continuous memory DTCs from the PCM.
- Is DTC P0620, P0625, P0626 or P065B set in the PCM?
Yes
REFER to Charging System Testing and Inspection.
No
GO to AC3.
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AC3 CHECK THE BATTERY CONDITION AND STATE OF CHARGE
- Ignition OFF.
- Check the battery condition and verify the battery is fully charged. Refer to Battery, Mounting and Cables Testing and Inspection.
- Is the battery OK and fully charged?
Yes
GO to AC4.
No
REFER to Charging System Testing and Inspection.
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AC4 CHECK THE DDM VOLTAGE SUPPLY
- Measure and record the voltage at the battery.
- Disconnect: DDM C568b.
- Ignition ON.
- Measure the voltage between the DDM C568b-1, circuit SBP12 (GN/RD), harness side and ground.
- Is the voltage within 0.2 volt of the recorded battery voltage?
Yes
GO to AC5.
No
REPAIR the circuit for high resistance. CLEAR the DTCs. REPEAT the self-test.
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AC5 CHECK THE DDM GROUND CIRCUIT
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the DDM C568b-24, circuit GD126 (BK/WH), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to AC6.
No
REPAIR the circuit for high resistance. TEST the system for normal operation.
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AC6 CHECK FOR CORRECT DDM OPERATION
- Connect: Negative Battery Cable.
- Disconnect the DDM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the DDM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new DDM. REFER to Driver Door Module (DDM) Service and Repair. 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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