Pinpoint Test AQ: DTC P0A0C:00
High-Voltage Traction Battery
Pinpoint Test AQ: DTC P0A0C:00
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 Battery Energy Control Module (BECM) checks for continuity of the high-voltage system interlock circuit. The interlock circuit must have continuity before high-voltage will be supplied to the vehicle. The interlock circuit voltage travels through each of the high-voltage components and high-voltage cables and back to the BECM. This fault will illuminate the stop safely hazard (red triangle) warning indicator and shut down the vehicle.
- DTC P0A0C:00 (High Voltage System Interlock Circuit Low: No Sub Type Information) - Fault sets when the BECM senses the interlock circuit is open or shorted to power for 5 seconds or more.
This pinpoint test is intended to diagnose the following:
- Air Conditioning Compressor Module (ACCM)
- BECM
- DC to DC Converter Control Module (DC/DC)
- Transmission Control Module (TCM) (part of Electronically Controlled Continuously Variable Transmission (eCVT))
- High-voltage cables
PINPOINT TEST AQ: DTC P0A0C:00
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.
NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.
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AQ1 CHECK FOR SHORT TO GROUND IN INTERLOCK CIRCUIT
WARNING: Never install the service disconnect plug with the high-voltage bussed electrical center (BEC) cover removed. Always install the cover prior to connecting the service disconnect plug. The high-voltage BEC cover prevents inadvertent contact with the high voltage which is present at several points under the cover. Failure to follow these instructions may result in serious personal injury or death.
- Ignition OFF.
- Depower the High Voltage Traction Battery (HVTB) system. Refer to High-Voltage Traction Battery Systems Depowering High-Voltage Traction Battery Systems Depowering.
- Disconnect: BECM C4237B.
- Measure the resistance between BECM C4237B-44, circuit J1-A44, harness side and ground; and between BECM C4237B-47, circuit J1-A47, harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to AQ8.
No
GO to AQ2.
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AQ2 CHECK FOR SHORT TO GROUND IN HIGH-VOLTAGE CABLES IN INTERLOCK CIRCUIT
- Disconnect: High-voltage BEC C4236B.
- Measure the resistance between high-voltage BEC C4236B-1, circuit CYB04 (VT/BN), harness side and ground; and between high-voltage BEC C4236B-2, circuit CYB03 (BN/YE), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to AQ4.
No
GO to AQ3.
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AQ3 CHECK FOR SHORT TO GROUND IN INTERLOCK CIRCUIT TO TCM
- Disconnect: TCM C1458C.
- Measure the resistance between high-voltage BEC C4236B-1, circuit CYB04 (VT/BN), harness side and ground; and between high-voltage BEC C4236B-2, circuit CYB03 (BN/YE), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
INSTALL a eCVT. REFER to Automatic Transaxle/Transmission - Electronically Controlled Continuously Variable Transmission (eCVT) Removal. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL new high-voltage cables. REFER to High-Voltage Cables Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AQ4 CHECK FOR SHORT TO GROUND IN INTERLOCK CIRCUIT TO ACCM AND DC/DC
- Disconnect: High-voltage BEC C4236A.
- Measure the resistance between high-voltage BEC C4236A-3, circuit CYB02 (WH/BN), harness side and ground; and between high-voltage BEC C4236A-4, circuit CYB03 (BN/YE), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to AQ7.
No
GO to AQ5.
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AQ5 CHECK FOR SHORT TO GROUND IN INTERLOCK CIRCUIT TO DC/DC
- Disconnect: DC/DC C1457A.
- Measure the resistance between high-voltage BEC C4236A-3, circuit CYB02 (WH/BN), harness side and ground; and between high-voltage BEC C4236A-4, circuit CYB03 (BN/YE), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
INSTALL a new DC/DC. REFER to High Voltage Converter/Inverter Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
GO to AQ6.
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AQ6 CHECK FOR SHORT TO GROUND IN INTERLOCK CIRCUIT TO ACCM
- Connect: DC/DC C1457A.
- Disconnect: ACCM C1469B.
- Measure the resistance between high-voltage BEC C4236A-3, circuit CYB02 (WH/BN), harness side and ground; and between high-voltage BEC C4236A-4, circuit CYB03 (BN/YE), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
INSTALL a new ACCM and A/C compressor assembly. REFER to Climate Control Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL new high-voltage cables. REFER to High-Voltage Cables Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AQ7 CHECK FOR SHORT TO GROUND AT HIGH-VOLTAGE BEC
- Remove the high-voltage BEC cover. Refer to the exploded view in Battery Pack Sensor Module (BPSM) Service and Repair.
- Disconnect: High-voltage BEC C4001.
- Disconnect: High-voltage BEC C4002.
- Measure the resistance between high-voltage BEC C4001-1, circuit J12-1, harness side and ground; and between high-voltage BEC C4001-3, circuit J1-A44, harness side and ground.
- Measure the resistance between high-voltage BEC C4002-1, circuit J12-1, harness side and ground; and between high-voltage BEC C4002-3, circuit J12-A47, harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
INSTALL a new high-voltage BEC. REFER to High-Voltage Bussed Electrical Center Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL a new HVTB (includes HVTB system wire harness). REFER to High-Voltage Traction Battery High-Voltage Traction Battery. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AQ8 CHECK FOR SHORT TO VOLTAGE IN INTERLOCK CIRCUIT
- Ignition ON.
- Measure the voltage between BECM C4237B-44, circuit J1-A44, harness side and ground; and between BECM C4237B-47, circuit J1-A47, harness side and ground.
- Is any voltage present?
Yes
GO to AQ9.
No
GO to AQ15.
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AQ9 CHECK FOR VOLTAGE IN HIGH-VOLTAGE CABLES IN INTERLOCK CIRCUIT
- Disconnect: High-voltage BEC C4236B.
- Measure the voltage between high-voltage BEC C4236B-1, circuit CYB04 (VT/BN), harness side and ground; and between high-voltage BEC C4236B-2, circuit CYB03 (BN/YE), harness side and ground.
- Is any voltage present?
Yes
GO to AQ10.
No
GO to AQ11.
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AQ10 CHECK FOR VOLTAGE IN INTERLOCK CIRCUIT TO TCM
- Disconnect: TCM C1458C.
- Measure the voltage between high-voltage BEC C4236B-1, circuit CYB04 (VT/BN), harness side and ground; and between high-voltage BEC C4236B-2, circuit CYB03 (BN/YE), harness side and ground.
- Is any voltage present?
Yes
INSTALL new high-voltage cables. REFER to High-Voltage Cables Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL a eCVT. REFER to Automatic Transaxle/Transmission - Electronically Controlled Continuously Variable Transmission (eCVT) Removal. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AQ11 CHECK FOR VOLTAGE IN INTERLOCK CIRCUIT TO ACCM AND DC/DC
- Disconnect: High-voltage BEC C4236A.
- Measure the voltage between high-voltage BEC C4236A-3, circuit CYB02 (WH/BN), harness side and ground; and between high-voltage BEC C4236A-4, circuit CYB03 (BN/YE), harness side and ground.
- Is any voltage present?
Yes
GO to AQ12.
No
GO to AQ14.
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AQ12 CHECK FOR VOLTAGE IN INTERLOCK CIRCUIT TO DC/DC
- Disconnect: DC/DC C1457A.
- Measure the voltage between high-voltage BEC C4236A-3, circuit CYB02 (WH/BN), harness side and ground; and between high-voltage BEC C4236A-4, circuit CYB03 (BN/YE), harness side and ground.
- Is any voltage present?
Yes
GO to AQ13.
No
INSTALL a new DC/DC. REFER to High Voltage Converter/Inverter Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AQ13 CHECK FOR VOLTAGE IN INTERLOCK CIRCUIT TO ACCM
- Connect: DC/DC C1457A.
- Disconnect: ACCM C1469B.
- Measure the voltage between high-voltage BEC C4236A-3, circuit CYB02 (WH/BN), harness side and ground; and between high-voltage BEC C4236A-4, circuit CYB03 (BN/YE), harness side and ground
- Is any voltage present?
Yes
INSTALL new high-voltage cables. REFER to High-Voltage Cables Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL a new ACCM and A/C compressor assembly. REFER to Climate Control Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AQ14 CHECK FOR VOLTAGE AT HIGH-VOLTAGE BEC
- Remove the high-voltage BEC cover. Refer to the exploded view in Battery Pack Sensor Module (BPSM) Service and Repair.
- Disconnect: High-voltage BEC C4001.
- Disconnect: High-voltage BEC C4002.
- Measure the voltage between high-voltage BEC C4001-1, circuit J12-1, harness side and ground; and between high-voltage BEC C4001-3, circuit J1-A44, harness side and ground.
- Measure the voltage between high-voltage BEC C4002-1, circuit J12-1, harness side and ground; and between high-voltage BEC C4002-3, circuit J1-A47, harness side and ground.
- Is any voltage present?
Yes
INSTALL a new HVTB (includes HVTB system wire harness). REFER to High-Voltage Traction Battery High-Voltage Traction Battery. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL a new high-voltage BEC. REFER to High-Voltage Bussed Electrical Center Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AQ15 CHECK FOR CORRECT BECM OPERATION
- Ignition OFF.
- Check the BECM harness and component side connectors for:
- corrosion.
- pushed-out/bent pins.
- Connect: BECM C4237B .
- Connect: Service Disconnect Plug.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes
INSTALL a new BECM. REFER to Battery Energy Control Module (BECM) Service and Repair. CLEAR the DTCs. 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 connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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