Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test J: U3003:16
- Refer to POWER DISTRIBUTION
for schematic and connector information.
Normal Operation and Fault Conditions
The BCMC receives voltage at all times from the BJB.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition BCMC U3003:16 Battery Voltage: Circuit Voltage Below Threshold A continuous and on-demand DTC that sets in the BCMC when the BCMC detects lower than expected battery voltage on the voltage supply input circuit. Possible Sources
- Wiring, terminals or connectors
- Charging system concern
- Battery concern
- BCMC (BJB)
- J1 RECHECK THE BCMC (BODY CONTROL MODULE C) DIAGNOSTIC TROUBLE CODES (DTCS)
- Ignition ON.
- Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs).
- Wait 10 seconds.
- Using a diagnostic scan tool, perform the BCMC self-test.
Is DTC U3003:16 still present?
Yes GO to J2 No The system is operating correctly at this time. The DTC may have been set due to a previous low battery voltage condition. CLEAR the DTC. - J2 CHECK FOR CHARGING SYSTEM DIAGNOSTIC TROUBLE CODES (DTCS) SET IN OTHER MODULES
- Using a diagnostic scan tool, retrieve all Continuous Memory Diagnostic Trouble Codes (CMDTCs).
Are any charging system Diagnostic Trouble Codes (DTCs) recorded?
Yes DIAGNOSE the charging system concern. REFER to the appropriate Battery and Charging article for procedure . No GO to J3 - J3 CHECK THE BATTERY CONDITION AND STATE OF CHARGE
- Check the battery condition and verify the battery is fully charged. REFER to: Battery .
Is the battery OK and fully charged?
Yes GO to J4 No If the battery is discharged, DIAGNOSE the cause of the low battery condition. REFER to: Battery . If the battery condition fails, INSTALL a new battery. REFER to: Battery . - J4 CHECK THE BCMC (BODY CONTROL MODULE C) VOLTAGE SUPPLY CIRCUIT
- Ignition OFF.
- Disconnect BCMC C1617A.
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead C1617A-1 Ground
IS the voltage greater than 11.5 volts?
Yes GO to J5 No REPAIR the circuit in question for high resistance. - J5 CHECK THE BCMC (BODY CONTROL MODULE C) GROUNDS
- Ignition OFF.
- Disconnect BCMC (BJB) C1035C.
- Disconnect BCMC (BJB) C1035E.
Is the resistance less than 3 ohms?
Yes GO to J6 No REPAIR the circuit in question for high resistance. - J6 CHECK FOR CORRECT BCMC (BODY CONTROL MODULE C) OPERATION
- Disconnect and inspect the BCMC connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect the BCMC connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new BCMC. REFER to: Body Control Module C (BCMC) . No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.