Pinpoint Test I: The Battery Control Module (BCM) Does Not Respond To The Scan Tool
Communications Network
Pinpoint Tests
Pinpoint Test I: The Battery Control Module (BCM) Does Not Respond To The Scan Tool
Refer to Wiring Diagram Set 14 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Module Communications Network for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 23 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Electronic Engine Controls - 2.3L for schematic and connector information. Diagrams By Number
Normal Operation
The Battery Control Module (BCM) is present on Hybrid vehicles only. The BCM communicates with the scan tool through the High Speed Controller Area Network (HS-CAN). Circuits VDB04 (WH/BU) (HS-CAN +) and VDB05 (WH) (HS-CAN -) provide the network connection to the BCM. Voltage for the BCM is provided by circuits CBB23 (BN/YE), SBB05 (GY/RD) and SBB15 (WH/RD). Ground is provided by circuits GD182 (BK/GY) and GD149 (BK/GY).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- BCM
PINPOINT TEST I: THE BCM DOES NOT RESPOND TO THE SCAN TOOL
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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I1 CHECK THE POWER TO THE BCM
WARNING: When servicing the high-voltage system, establish a buffer zone per the specified procedure. Failure to follow this instruction may result in serious personal injury or death.
WARNING: Turn OFF the ignition switch for a minimum of 5 minutes before removing high-voltage cables. High-voltage cables and wiring are orange in color. The nominal high-voltage traction battery voltage (HVTB) is 330 V DC. Failure to follow these instructions may result in serious personal injury or death.
WARNING: Depower the high-voltage traction battery (HVTB) before carrying out any removal or installation procedures affecting the high-voltage battery system. Failure to follow this instruction may result in serious personal injury or death.
WARNING: Wear high-voltage insulated safety gloves and a face shield when working with high-voltage batteries or cables. The high-voltage insulated safety gloves should be of the appropriate safety and protection rating. Inspect the gloves before use and always wear them with the leather outer glove. Any hole in the rubber insulating glove is a potential entry point for high-voltage. Failure to follow these instructions may result in serious personal injury or death.
- Ignition OFF.
- Disconnect: BCM C4227a.
- Ignition ON.
- Measure the voltage between the BCM, harness side and ground as follows:
- Are the voltages greater than 10 volts?
Yes
GO to I2.
No
VERIFY the Battery Junction Box (BJB) fuse 8 (10A), fuse 26 (20A), and fuse 15 (50A) are 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.
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I2 CHECK THE BCM GROUNDS
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the BCM, harness side and ground as follows:
- Are the resistances less than 5 ohms?
Yes
GO to I3.
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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I3 CHECK THE HS-CAN CIRCUITS BETWEEN THE BCM AND THE DLC FOR AN OPEN
- Measure the resistance between the BCM C4227a-29, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
- Measure the resistance between the BCM C4227a-28, 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 I4.
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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I4 CHECK FOR CORRECT BCM OPERATION
NOTE: Do not disconnect the high voltage cables or connectors in the following step.
- Disconnect the BCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the BCM connectors and make they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new High Voltage Traction Battery (HVTB). 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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