Pinpoint Test J: DTC U3003:62
High-Voltage Converter/Inverter
Pinpoint Test J: DTC U3003:62
Refer to Wiring Diagram Set 12 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ 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. The DC/DC also monitors the PCM relay control circuit voltage and compares that voltage to the voltage sensed internally at the B+ terminal. If the 2 voltages vary by greater than 4.3 volts, the DC/DC sets DTC U3003:62 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 be drained. Reduced or no functionality of 12-volt systems (headlamps, HVAC blower motor, etc.) may also be noticed.
- DTC U3003:62 (Battery Voltage: Signal Compare Failure) - Sets when the DC/DC senses greater than 4.3 volts difference between the DC/DC B+ terminal and the PCM relay control circuit.
This pinpoint test is intended to diagnose the following:
- DC/DC B+ cable mounting
- B+ cable fuse (200A)
- 12-volt battery cables
- Wiring, terminals or connectors
- DC/DC
PINPOINT TEST J: DTC U3003:62
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J1 CHECK THE PCM MODULE SUPPLY VOLTAGE (VPWR) PID
- Measure and record the voltage of the battery.
- Connect the scan tool.
- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- Monitor the VPWR PID.
- Does the VPWR PID match battery voltage?
Yes
GO to J2.
No
CARRY OUT a self-test of the PCM. RECORD any DTCs and REFER to Computers and Control Systems Information.
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J2 CHECK THE B+ CABLE
- Measure the voltage between DC/DC C1457B, circuit SDC02 (RD), and DC/DC C1457C, circuit GD108 (BK/VT), harness side.
- Does the DC/DC voltage match battery voltage?
Yes
GO to J3.
No
VERIFY the B+ cable fuse (200A) is OK. If OK, REPAIR the affected circuit(s). If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation. Diagrams By Number
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J3 MEASURE VOLTAGE DROP OF DC/DC B+ CIRCUIT
- Ignition ON.
- With the headlamps ON and the blower on high, measure the voltage between DC/DC C1457B, circuit SDC02 (RD), harness side and the positive battery terminal.
- Is the voltage drop less 0.5 volt?
Yes
GO to J4.
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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J4 CHECK THE PCM RELAY CONTROL INPUT TO THE DC/DC
- Ignition OFF.
- Disconnect: DC/DC C1457D.
- Ignition ON.
- Measure the voltage between DC/DC C1457D-7, circuit CBK03 (GY), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to J5.
No
VERIFY the Battery Junction Box (BJB) fuse 47 (10A) is OK. If OK, REPAIR circuit CBK03 (GY). If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation. Diagrams By Number
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J5 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 U3003:62 reported?
Yes
INSTALL a new DC/DC. REFER to Direct Current/Direct Current (DC/DC) Converter Service and Repair. 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 loose or corroded connection. REPEAT the self-test. TEST the system for normal operation.
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