Pinpoint Test H: DTC P0AA1:00 or P0AA2:00
High-Voltage Traction Battery
Pinpoint Test H: DTC P0AA1:00 or P0AA2:00
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
When the ignition is turned on, the Battery Energy Control Module (BECM) makes various vehicle checks. If these checks are normal, the BECM sends a signal to the contactor to close and supply high-voltage power to the vehicle. The stop safely hazard (red triangle) warning indicator will illuminate for both DTCs. For DTC P0AA1:00, the vehicle will not start at next ignition cycle. For P0AA2:00, the vehicle is shut down.
- DTC P0AA1:00 (Hybrid Battery Positive Contactor Circuit Stuck Closed: No Sub Type Information) - If the contactor is stuck closed, this DTC will be set.
- DTC P0AA2:00 (Hybrid Battery Positive Contactor Circuit Stuck Open: No Sub Type Information) - If the contactor is stuck open for 2 seconds, this DTC will be set. Reports as a continuous memory (historical) DTC only.
This pinpoint test is intended to diagnose the following:
- High-voltage Bussed Electrical Center (BEC)
- BECM
- High Voltage Traction Battery (HVTB)
PINPOINT TEST H: DTC P0AA1:00 OR P0AA2:00
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.
-------------------------------------------------
H1 CHECK THE BATTERY PACK SENSOR MODULE (BPSM)
- Ignition OFF.
- INSTALL a new Battery Pack Sensor Module (BPSM). REFER to Battery Pack Sensor Module (BPSM) Service and Repair.
- Enter the following diagnostic mode on the scan tool: Clear DTCs - BECM.
- Enter the following diagnostic mode on the scan tool: Self Test - BECM.
- Is DTC P0AA1 or P0AA2 present?
Yes
GO to H2.
No
Repair is complete. TEST the system for normal operation.
-------------------------------------------------
H2 MEASURE VOLTAGE AT BECM CONNECTOR
- Ignition ON.
- Measure voltage between BECM C4237B-58, circuit J1-A58, harness side and ground by back-probing the BECM connector; and between BECM C4237B-59, circuit J1-A59, harness side and ground by back-probing the BECM connector.
- Is the voltage between 5-6 volts?
Yes
GO to H3.
No
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.
-------------------------------------------------
H3 CHECK CONTACTOR WIRING
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 HVTB system. Refer to High-Voltage Traction Battery Systems Depowering High-Voltage Traction Battery Systems Depowering.
- Disconnect the 12-volt battery. Refer to Battery, Mounting and Cables Battery Disconnect.
- Remove the high-voltage BEC cover. Refer to the exploded view in Battery Pack Sensor Module (BPSM) Service and Repair.
- Disconnect: BECM C4237B.
- Disconnect: High-voltage BEC C4236D.
- Measure the resistance between high-voltage BEC C4236D-1, circuit J1-A58, harness side and BECM C4237B-58, circuit J1-A58, harness side; and between high-voltage BEC C4236D-2, circuit J1-A59 harness side and BECM C4237B-59, circuit J1-A59, harness side.
- Are the resistances less than 5 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.
-------------------------------------------------