Pinpoint Test A: DTC P0A12:16

High-Voltage Converter/Inverter

Pinpoint Test A: DTC P0A12:16

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 PCM relay control circuit voltage. If the PCM relay control circuit to the DC/DC becomes open or voltage is low, DTC P0A12:16 sets and the DC/DC maintains standard operation of the charging system, though a delay in vehicle start-up time may occur.

- DTC P1A12:16 (DC/DC Converter Enable Circuit Low: Circuit Voltage Below Threshold) - Sets when the PCM relay control circuit provides less than 7 volts to DC/DC C1457D-7.

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- 12-volt battery cables
- DC/DC


PINPOINT TEST A: DTC P0A12:16

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A1 CHECK THE BATTERY POSITIVE CIRCUIT VOLTAGE

- Ignition OFF.
- Measure the voltage between DC/DC C1457B, B+ terminal and ground.




- START the vehicle (Ready Indicator light ON).
- Measure the voltage between DC/DC C1457B, B+ terminal and ground.




- Did the voltage increase with the ignition ON?

Yes
GO to A3.

No
GO to A2.

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A2 CHECK THE DC TO DC VOLTAGE CONVERTER STATUS (EnableStat) PID

- Connect the scan tool.
- Enter the following diagnostic mode on the scan tool: DataLogger - DC/DC.
- Monitor the EnableStat PID.
- Does the PID read Enable?

Yes
GO to A4.

No
CARRY OUT self-test of the PCM and Battery Energy Control Module (BECM). REFER to Computers and Control Systems Information and High Voltage Traction Battery Testing and Inspection for further diagnosis.

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A3 CHECK THE PCM RELAY CONTROL INPUT TO THE DC/DC

- Ignition OFF.
- Disconnect: DC/DC C1457D.
- START the vehicle (Ready Indicator light 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 A4.

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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A4 CLEAR DTCs AND CARRY OUT SELF-TEST OF THE DC/DC

- Using the scan tool, clear the DC/DC DTCs.
- Wait a minimum of 65 seconds before carrying out the next step.
- Enter the following diagnostic mode on the scan tool: Self Test - DC/DC.
- Is DTC P0A12:16 reported?

Yes
INSTALL a new DC/DC. REFER to Direct Current/Direct Current (DC/DC) Converter Service and Repair. REPEAT the self-test. TEST the system for normal operation.

No
Concern is not present at this time. INSPECT the PCM relay control input to DC/DC C1457D-7, circuit CBK03 (GY) for intermittent faults. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation.

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