Pinpoint Test K: DTC P0AAE:00 or P0AAF:00
High-Voltage Traction Battery
Pinpoint Test K: DTC P0AAE:00 or P0AAF: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
With the ignition in the ON position and the engine running or OFF, the Battery Pack Sensor Module (BPSM) monitors the High Voltage Traction Battery (HVTB) internal temperature. The BPSM communicates the HVTB temperature (in addition to other information) to the Battery Energy Control Module (BECM) through a dedicated Controller Area Network (CAN). There is also a HVTB inlet air temperature sensor mounted to the inlet air duct which monitors inlet air temperature to the HVTB. The BECM uses the information from the various temperature sensors to control and maintain HVTB temperature by controlling the HVTB cooling fan. The ideal HVTB temperature is 25°C (77°F) with a desired range of 20°C (68°F) to 30°C (86°F).
- P0AAE:00 (Hybrid Battery Pack Air Temperature Sensor A Circuit Low: No Sub Type Information) - Fault sets if the BECM senses greater than 90°C (194°F) from the HVTB inlet air temperature sensor for 10 seconds or more. Extreme ambient temperatures could also set this DTC.
- P0AAF:00 (Hybrid Battery Pack Air Temperature Sensor A Circuit High: No Sub Type Information) - Fault sets if the BECM senses less than -45°C (-49°F) from the HVTB inlet air temperature sensor for 10 seconds or more. Extreme ambient temperatures could also set this DTC.
This pinpoint test is intended to diagnose the following:
- HVTB inlet air temperature sensor
- BECM
- HVTB
PINPOINT TEST K: DTC P0AAE:00 OR P0AAF: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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K1 MEASURE THERMISTOR RESISTANCE FROM BECM
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.
- Remove the high-voltage Bussed Electrical Center (BEC) cover. Refer to the exploded view in Battery Pack Sensor Module (BPSM) Service and Repair.
- Disconnect: Battery Energy Control Module (BECM) C4237B.
- Measure the resistance between BECM C4237B-39, circuit J1-A39, harness side and BECM C4237B-41, circuit J1-A41, harness side. Use the following table to determine if the resistance values are correct.
- Is the resistance value correct for the temperature?
Yes
GO to K3.
No
GO to K2.
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K2 MEASURE THERMISTOR RESISTANCE AT THE THERMISTOR
- Disconnect: HVTB Inlet Air Temperature Sensor C4253.
- Measure the resistance between HVTB inlet air temperature sensor C4253 pin 1 and pin 2, component side. Use the following table to determine if the resistance values are correct.
- Is the resistance value correct for the temperature?
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 HVTB inlet air temperature thermistor. REFER to High-Voltage Traction Battery Inlet Air Temperature Sensor Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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K3 CHECK FOR CORRECT BECM OPERATION
- Ignition OFF.
- Check the BECM harness and component side connectors for:
- corrosion.
- pushed-out/bent pins.
- Connect the BECM and make sure the connectors seat correctly.
- 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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