Pinpoint Test H: DTC U3003:16
High-Voltage Converter/Inverter
Pinpoint Tests
Pinpoint Test H: DTC U3003:16
Refer to Wiring Diagram Set 12 (Fusion/Milan/MKZ, Fusion Hybrid/Milan Hybrid), Charging System for schematic and connector information. Diagrams By Number
Normal Operation
The DC to DC Converter Control Module (DC/DC) monitors the 12-volt battery system voltage internally at the B+ terminal of the DC/DC. If the voltage drops below 10.5 volts while the ignition is ON, the DC/DC sets DTC U3003:16 and requests CHECK CHARGING SYSTEM be displayed in the message center. The DC/DC will be in standby mode (DC/DC disabled) and the 12-volt battery will eventually be drained. Reduced or no functionality of 12-volt systems (headlamps, HVAC blower motor, etc.) may also be noticed.
- DTC U3003:16 (Battery Voltage: Circuit Voltage Below Threshold) - Sets if the 12-volt battery system voltage is less than 10.5 volts.
This pinpoint test is intended to diagnose the following:
- 12-volt battery
- 12-volt battery cables
- DC/DC
PINPOINT TEST H: DTC U3003:16
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H1 CHECK THE DC/DC DTCs
- Review the DTCs recorded during Inspection and Verification.
- Are any DTCs other than U3003:16 present?
Yes
REPAIR all other DC/DC DTCs before repairing U3003:16. GO to the DC to DC Converter Control Module (DC/DC) DTC Chart. Diagnostic Trouble Code Tests and Associated Procedures
No
GO to H2.
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H2 TEST BATTERY CONDITION
- Ignition OFF.
- Carry out the battery condition test. Refer to Battery. Pinpoint Tests
- Did the battery pass the condition test?
Yes
GO to H3.
No
INSTALL a new battery. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation.
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H3 CHECK VOLTAGE AT THE DC/DC
- Start the engine.
- Turn the headlamps on and the blower on high.
- Measure the voltage of the battery.
- Measure the voltage between DC/DC C1457B, circuit SDC02 (RD), harness side and DC/DC C1457C, circuit GD108 (BK/VT), harness side.
- Does the DC/DC voltage match battery voltage?
Yes
GO to H5.
No
GO to H4.
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H4 MEASURE VOLTAGE DROP OF DC/DC B+ CIRCUIT
- Measure the voltage between DC/DC C1457B, circuit SDC02 (RD), harness side and the positive battery terminal.
- Is the voltage drop less than 0.5 volt?
Yes
REPAIR DC/DC B- circuit GD108 (BK/VT) or INSTALL a new cable, if necessary. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation.
No
REPAIR DC/DC B+ circuit SDC02 (RD) or INSTALL a new cable, if necessary. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation.
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H5 CLEAR DTCs AND CARRY OUT SELF-TEST OF THE DC/DC
- Connect the scan tool.
- Using the scan tool, clear the DC/DC DTCs.
- Enter the following diagnostic mode on the scan tool: Self Test - DC/DC.
- Is DTC U3003:16 reported?
Yes
INSTALL a new DC/DC. REFER to Hybrid Drive Systems. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a discharged battery. REPEAT the self-test. TEST the system for normal operation.
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