Pinpoint Test I: DTC B2172 - Inertia Fuel Shutoff (IFS) Switch Input Circuit Open
High-Voltage Traction Battery
Pinpoint Test I: DTC B2172 - Inertia Fuel Shutoff (IFS) Switch Input Circuit Open
Refer to Wiring Diagram Set 12, Charging System for schematic and connector information Electrical Diagrams.
Normal Operation
With the engine running, the battery power off (BPO) function may be triggered by the Inertia Fuel Shutoff (IFS) switch or the High Voltage Cut Off Switch opening, a high-voltage interlock circuit opening, the electrical interlock (EL I) circuit opening (fuse protected by the Battery Junction Box (BJB) fuse 26 [20A]) or if the contactor box within the Battery Control Module - High Voltage Traction Battery (BCM-HVTB) requests a BPO mode. If the IFS (Inertia Fuel Shutoff) switch opens and causes the BPO mode to occur and DTCs are set. Also, if the IFS (Inertia Fuel Shutoff) 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-HVTB (Battery Control Module - High Voltage Traction Battery) 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 (Inertia Fuel Shutoff) switch circuit(s) is open, the DTC is set.
This pinpoint test is intended to diagnose the following:
- IFS (Inertia Fuel Shutoff) switches
- Circuitry
- High Voltage Traction Battery (HVTB)
PINPOINT TEST I : DTC B2172 - Inertia Fuel Shutoff (IFS) SWITCH INPUT CIRCUIT OPEN
I1 CHECK THE IFS (Inertia Fuel Shutoff) SWITCH AND THE HIGH VOLTAGE CUT OFF SWITCH
- NOTE: The IFS (Inertia Fuel Shutoff) switch is located on the RH kick panel and the High Voltage Cut Off Switch is located near the RH rear tail lamp behind the jack.
Check the IFS (Inertia Fuel Shutoff) switch and the High Voltage Cut Off Switch, verify that the reset buttons on the top of the switches are pushed (closed).
Are the switch reset buttons closed?
Yes
GO to I2.
No
INSTALL a new switch as necessary. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation. If DTC B2172 is still present GO to I2.
I2 CHECK THE IFS (Inertia Fuel Shutoff) SWITCH POWER INPUT CIRCUITS
- Ignition OFF.
- Disconnect: Battery Control Module - High Voltage Traction Battery (BCM-HVTB) C4227A.
- Ignition ON.
- Measure the voltage between ground and:
- BCM-HVTB (Battery Control Module - High Voltage Traction Battery) C4227A-7, circuit CYB15 (GN), harness side.
- BCM-HVTB (Battery Control Module - High Voltage Traction Battery) C4227A-23, circuit CYB15 (GN), harness side.
Is the voltage greater than 10 volts at C4227A-7 and C4227A-23?
Yes
GO to I7.
No
If there is no voltage at either pin GO to I3. If voltage is available at one pin only. REPAIR circuit CYB15 (GN) and TEST the system for normal operation.
I3 CHECK THE HIGH VOLTAGE CUT OFF SWITCH POWER INPUT CIRCUITS
- Ignition OFF.
- Disconnect: High Voltage Cut Off Switch C4229.
- Ignition ON.
- Measure the voltage between the high voltage cut off switch C4229-2, circuit CE911(VT/WH), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to I5.
No
GO to I4.
I4 CHECK THE IFS (Inertia Fuel Shutoff) SWITCH SUPPLY CIRCUIT
- Ignition OFF.
- Disconnect: IFS (Inertia Fuel Shutoff) Switch C392.
- Measure the voltage between the IFS (Inertia Fuel Shutoff) switch C392-2, circuit CBB26 (BU/WH), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to I6.
No
VERIFY the BJB (Battery Junction Box) fuse 26 (20A). If the fuse is OK. REPAIR the open in circuit CBB26 (BU/WH). If the fuse is not OK. REFER to the wiring diagrams to identify the short to ground Electrical Diagrams.
I5 CHECK THE REAR HIGH VOLTAGE CUT OFF SWITCH RESISTANCE
- Measure the resistance between the high voltage cut off switch C4229-1, component side and the high voltage cut off switch C4229-2, component side.
Is the resistance less than 5 ohms?
Yes
REPAIR the open in circuit CYB15 (GN). CLEAR the DTCs and TEST the system for normal operation.
No
INSTALL a new high voltage cut off switch. CLEAR the DTCs and TEST the system for normal operation.
I6 CHECK THE IFS (Inertia Fuel Shutoff) SWITCH RESISTANCE
- Measure the resistance between the IFS (Inertia Fuel Shutoff) switch C392-2, component side and the IFS (Inertia Fuel Shutoff) switch C392-1, component side.
Is the resistance less than 5 ohms?
Yes
REPAIR the open in circuit CE911 (VT/WH). CLEAR the DTCs and TEST the system for normal operation.
No
INSTALL a new IFS (Inertia Fuel Shutoff) switch. CLEAR the DTCs and TEST the system for normal operation.
I7 CHECK THE BCM-HVTB (Battery Control Module - High Voltage Traction Battery) GROUND CIRCUIT
- Measure the voltage between BCM-HVTB (Battery Control Module - High Voltage Traction Battery) C4227A-7 circuit CYB15 (GN) harness side and:
- BCM-HVTB (Battery Control Module - High Voltage Traction Battery) C4227A-30 circuit GD182 (BK/GY) harness side.
- BCM-HVTB (Battery Control Module - High Voltage Traction Battery) C4227A-31 circuit GD182 (BK/GY) harness side.
Are the voltages at least 10 volts?
Yes
GO to I8.
No
REPAIR circuit GD182 (BK/GY). CLEAR the DTC. TEST the system for normal operation.
I8 CHECK RETURNING DTCs
- Ignition OFF.
- Connect: BCM-HVTB (Battery Control Module - High Voltage Traction Battery) C4227A.
- Connect the scan tool.
- Ignition ON.
- Using the scan tool, clear all BCM-HVTB (Battery Control Module - High Voltage Traction Battery) DTCs.
- Enter the following diagnostic mode on the scan tool: Self Test- BCM-HVTB (Battery Control Module - High Voltage Traction Battery).
Is DTC B2172 present?
Yes
INSTALL a new BCM-HVTB (Battery Control Module - High Voltage Traction Battery). REFER to High-Voltage Traction Battery . TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a poor or intermittent connection.