Pinpoint Test L: The DC to DC Converter Control Module (DC/DC) Does Not Respond To The Scan Tool
Communications Network
Pinpoint Test L: The DC to DC Converter Control Module (DC/DC) Does Not Respond To The Scan Tool
Refer to Wiring Diagram Set 14 (Fusion/Milan/MKZ, Fusion Hybrid, Milan Hybrid, MKZ Hybrid), Module Communications Network for schematic and connector information. Diagrams By Number
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) is present on hybrid vehicles only. The DC/DC communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- DC/DC
PINPOINT TEST L: THE DC/DC DOES NOT RESPOND TO THE SCAN TOOL
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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L1 CHECK THE DC/DC VOLTAGE SUPPLY CIRCUITS FOR AN OPEN
WARNING: To prevent the risk of high-voltage shock, always follow precisely all warnings and service instructions, including instructions to depower the system. The high-voltage hybrid system utilizes approximately 300 volts DC, provided through high-voltage cables to its components and modules. The high-voltage cables and wiring are identified by orange harness tape or orange wire covering. All high-voltage components are marked with high-voltage warning labels with a high-voltage symbol. Failure to follow these instructions may result in serious personal injury or death.
WARNING: Always wear high-voltage insulated safety gloves with leather outer gloves and a face shield when servicing the battery pack sensor module (BPSM) and never remove the high-voltage BPSM connector unless directed by a service procedure. High voltage is present at the BPSM at all times, even with service disconnect plug removal. Depowering the system will not remove voltage from the BPSM connector with the orange harness. Follow all service instructions. Failure to follow these instructions may result in serious personal injury or death.
- Ignition OFF.
- Disconnect: DC/DC C1457d .
- Ignition ON.
- Measure the voltage between the DC/DC C1457d-7, circuit CBK03 (GY), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to L2.
No
VERIFY the Battery Junction Box (BJB) fuse 47 (10A) is OK. If OK, REPAIR the circuit in question. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the network test with the scan tool. Diagrams By Number
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L2 CHECK THE DC/DC GROUNDS
- Ignition OFF.
- Disconnect: Negative Battery Cable .
- NOTE: Do not disconnect the DC/DC ground eyelet C1457c. The measurement is taken between the negative battery eyelet and chassis ground.
- Measure the resistance between the DC/DC C1457c-1, circuit GD108 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to L3.
No
REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
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L3 CHECK THE HS-CAN CIRCUITS BETWEEN THE DC/DC AND THE DLC FOR AN OPEN
- Measure the resistance between the DC/DC C1457d-9, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
- Measure the resistance between the DC/DC C1457d-6, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.
- Are the resistances less than 5 ohms?
Yes
CONNECT the negative battery cable. GO to L4.
No
REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
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L4 CHECK FOR CORRECT DC/DC OPERATION
NOTE: Do not disconnect the high voltage cables or connectors in the following step.
- Disconnect the DC/DC LOW VOLTAGE connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the DC/DC LOW VOLTAGE 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 DC/DC. REFER to High Voltage Converter/Inverter . CLEAR the DTCs. REPEAT the network test with the scan tool.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the network test with the scan tool.
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