Pinpoint Test AW: DTC B1318
Seats
Pinpoint Test AW: DTC B1318
Refer to Wiring Diagram Set 13 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Power Distribution/SJB for schematic and connector information. Diagrams By Number
Normal Operation
The Driver Seat Module (DSM) 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 DSM detects battery voltage below 10 volts on circuit SBB32.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- High circuit resistance
- DSM
PINPOINT TEST AW: 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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AW1 RECHECK THE DSM DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DSM Self-Test.
- Clear the DTCs. Repeat the DSM self-test.
- Is DTC B1318 still present?
Yes
GO to AW2.
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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AW2 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 AW3.
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AW3 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 AW4.
No
REFER to Charging System Testing and Inspection.
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AW4 CHECK THE DSM VOLTAGE SUPPLY
- Measure and record the voltage at the battery.
- Disconnect: DSM C3299a.
- Ignition ON.
- Measure the voltage between the DSM C3299a-1, circuit SBB32 (VT/RD), harness side and ground.
- Is the voltage within 0.2 volt of the recorded battery voltage?
Yes
GO to AW5.
No
REPAIR the circuit for high resistance. CLEAR the DTCs. REPEAT the self-test.
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AW5 CHECK THE DSM GROUND CIRCUITS
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Disconnect: DSM C3299b.
- Measure the resistance between the DSM C3299a-2, circuit GD126 (BK/WH), harness side and ground.
- Measure the resistance between the DSM C3299b-24, circuit GD126 (BK/WH), harness side and ground.
- Are the resistances less than 5 ohms?
Yes
CONNECT the negative battery cable. GO to AW6.
No
REPAIR the circuit for high resistance. CONNECT the negative battery cable. TEST the system for normal operation.
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AW6 CHECK FOR CORRECT DSM OPERATION
- Disconnect the DSM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the DSM 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 DSM. REFER to Driver Seat Module (DSM) 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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