Pinpoint Test I: DTC B2172
High-Voltage Traction Battery
Pinpoint Tests
Pinpoint Test I: DTC B2172
Refer to Wiring Diagram Set 12 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Charging System for schematic and connector information. Diagrams By Number
Normal Operation
With the engine running, the battery power off function may be triggered by an open condition in the front and/or rear Inertia Fuel Shutoff (IFS) switches, the high-voltage interlock circuit, the electrical interlock (EL I) circuit (fuse protected by the Battery Junction Box (BJB) fuse 26 [5A]) or if the contactor box within the Battery Control Module (BCM) requests a battery power off mode. If the IFS switch opens and causes the battery power off mode to occur, no DTCs are set. Also, if the IFS switch is open, a power reset indicator in the Instrument Cluster (IC) illuminates. With the ignition switch in the ON position and the engine ON or OFF (the engine must have run at least once after the key was cycled to ON), the BCM monitors the contactors continuously. During a power down (key OFF) sequence, one or both of the contactors may set this DTC if they fail.
- DTC B2172 (IFS Switch Input Circuit Open) - If the BCM detects that the IFS switch circuit(s) is open, the DTC is set.
This pinpoint test is intended to diagnose the following:
- IFS switches
- Circuitry
- High Voltage Traction Battery (HVTB)
PINPOINT TEST I: DTC B2172
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I1 CHECK THE FRONT AND REAR IFS SWITCHES
- NOTE: The front IFS switch is located on the RH kick panel and the rear IFS switch is located near the RH rear tail lamp behind the jack.
- Check the front and rear IFS switch, verify that the reset buttons on the top of the switches are pushed (closed).
- Are the IFS switches okay?
Yes
GO to I2.
No
INSTALL a new front and/or rear IFS switch. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation.
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I2 CHECK FRONT AND REAR IFS CIRCUITS CE911 (VT/WH) AND CBB24 (VT/GN) FOR AN OPEN
- Ignition OFF.
- Disconnect: Front IFS Switch C392.
- Disconnect: Rear IFS Switch C4229.
- Ignition ON.
- Measure the voltage between front IFS switch C392-2, circuit CBB24 (VT/GN), harness side and ground.
- Measure the voltage between rear IFS switch C4229-2, circuit CE911 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to I3.
No
CHECK the IFS switch and circuits for a fault. If OK, REPAIR circuit CE911 (VT/WH). CLEAR the DTC. TEST the system for normal operation.
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I3 CHECK THE FRONT AND REAR IFS SWITCH RESISTANCES
- Ignition OFF.
- Measure the resistance between front IFS switch C392, pin 1 and pin 2, component side.
- Measure the resistance between rear IFS switch C4229, pin 1 and pin 2, component side.
- Are the resistances less than 5 ohms?
Yes
GO to I4.
No
INSTALL a new IFS switch(es). CLEAR the DTC. TEST the system for normal operation.
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I4 CHECK THE IFS SWITCH POWER INPUT CIRCUITS
- Connect: Front IFS Switch C392.
- Connect: Rear IFS Switch C4229.
- Disconnect: BCM C4227A.
- Ignition ON.
- Check the voltage to the IFS switch input circuits between BCM C4227A-7 and C4227A-23, circuit CYB15 (GN) harness side and chassis ground.
- Are the voltages at least 10 volts?
Yes
GO to I5.
No
REPAIR circuit CYB15 (GN). CLEAR the DTC. TEST the system for normal operation.
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I5 CHECK THE BCM GROUND CIRCUIT
- Measure the voltage between BCM C4227A-7 and BCM C4227A-23 circuit CYB15 (GN) harness side and BCM C4227A-30 and/or BCM C4227A-31 circuit GD182 (BK/GY) harness side.
- Are the voltages at least 10 volts?
Yes
INSTALL a new HVTB. REFER to High-Voltage Traction Battery Removal and Replacement. TEST the system for normal operation.
No
REPAIR circuit GD182 (BK/GY). CLEAR the DTC. TEST the system for normal operation.
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