DTC B1318 [BCM]

id0902f5831000

DTC B1318

Battery voltage low
DETECTION CONDITION
Input voltage from the battery is excessively low
POSSIBLE CAUSE
•  Open circuit in wiring harness between BCM terminal 4A and battery
•  Open circuit in wiring harness between BCM terminal 2B and battery
•  Open circuit in wiring harness between BCM terminal 2A and battery
•  Short to GND in wiring harness between BCM terminal 4A and battery
•  Short to GND in wiring harness between BCM terminal 2B and battery
•  Short to GND in wiring harness between BCM terminal 2A and battery
•  Battery malfunction
•  Generator malfunction
•  BCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
INSPECT DTC FROM PCM
•  Connect the M-MDS to the DLC-2.
•  Are any DTCs from the PCM displayed?
Yes
Perform DTC inspection.
(See DTC TABLE [MZI-3.7 (PCM CONNECTOR (2 TYPES))].)
(See DTC TABLE [MZI-3.7 (PCM CONNECTOR (3 TYPES))].)
Go to Step 5.
No
Go to the next step.
2
INSPECT BCM CONNECTOR
•  Disconnect the BCM connector.
•  Inspect the BCM connector terminals for poor connection (such as damaged/pulled-out pins, and corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 5.
No
Go to the next step.
3
INSPECT BCM POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT
•  Disconnect the negative battery cable.
•  Disconnect the positive battery cable.
•  Turn the ignition switch to ON.
•  Inspect for continuity between following terminals:
―  BCM terminal 4A (wiring harness-side) — battery positive terminal (wiring harness-side)
―  BCM terminal 2B (wiring harness-side) — battery positive terminal (wiring harness-side)
―  BCM terminal 2A (wiring harness-side) — battery positive terminal (wiring harness-side)
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for a possible open circuit, then go to Step 5.
4
INSPECT BCM POWER SUPPLY CIRCUIT FOR SHORT TO GND
•  Inspect for continuity between following terminals:
―  BCM terminal 4A (wiring harness-side) — body GND
―  BCM terminal 2B (wiring harness-side) — body GND
―  BCM terminal 2A (wiring harness-side) — body GND
•  Is there continuity?
Yes
Repair or replace the wiring harness for a possible short to GND, then go to the next step.
No
Go to the next step.
5
VERIFY TROUBLESHOOTING COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Clear the DTC from the BCM memory using the M-MDS.
•  Turn the ignition switch to LOCK position then ON position.
•  Is the same DTC present?
Yes
Replace the BCM.
(See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION.)
No
DTC troubleshooting completed.