Circuit/System Testing
Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.
The High Voltage Disabling procedure includes the following steps:
- Identify how to disable high voltage.
- Identify how to test for the presence of high voltage.
- Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.
Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:
- Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors.
- Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors.
- Visually and functionally inspect the gloves before use.
- Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.
Failure to follow the procedures may result in serious injury or death.
Hybrid Battery Pack Voltage Diagnosis
- Vehicle OFF, disable the high voltage at the A4 Hybrid/EV Battery Pack. Refer to High Voltage Disabling
- Remove the S15 manual service disconnect.
- Test for less than 10 Ω across the S15 manual service disconnect fuse terminals 1 and 2, X2.
- If 10 Ω or greater
Replace the S15 manual service disconnect and repeat Circuit/System Verification.
- Go to next step: If less than 10 Ω
- If 10 Ω or greater
- Remove the A4 hybrid/EV battery pack cover. Refer to High Voltage Battery Cover Replacement
- Disconnect the A28 hybrid/EV battery contactor assembly high voltage connectors X1 and X2.
- Install a known good S15 manual service disconnect.
- Test for 128.5 - 360V between the X2 negative (300V) C4A and X1 positive (300V) C4H battery cable terminals.
- If not within the specified range
Replace the A4 Hybrid/EV Battery Pack. After the repair is complete with a scan tool, the Clear Secured High Voltage DTCs reset function must be performed.
- Go to next step: If within the specified range
- If not within the specified range
- Disconnect the A28 hybrid/EV battery contactor assembly high voltage sense circuit connector X5.
- Reconnect the A28 hybrid/EV battery contactor assembly high voltage connectors X1 and X2.
- Test for 128.5 - 360V between the X5 terminal 1 negative (300 V) and terminal 2 positive (300 V) at the A28 hybrid/EV battery contactor assembly.
- If not within the specified range
Replace the A28 Hybrid/EV Battery Contactor Assembly or the sense circuit fuse(s) as applicable.
- Go to next step: If within the specified range
- If not within the specified range
- Remove the S15 manual service disconnect.
- Disconnect K114B hybrid/EV powertrain control module 2 connector X6.
- Test for infinite resistance between high voltage sense circuit terminals 2 and 7, X6 and ground.
- If less than infinite resistance
Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- If less than infinite resistance
- Test for less than 2 Ω in each high voltage sense circuit end to end.
- If 2 Ω or greater
Repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω
- If 2 Ω or greater
- Replace the K114B Hybrid/EV Powertrain Control Module 2.
- After the repair is complete, the Clear Secured High Voltage DTCs reset function must be performed.
High voltage circuits should only be tested using a digital multimeter (DMM) and test leads with at least a CAT III rating, such as the J 39200-A Digital Multimeter. Failure to follow the procedures may result in serious injury or death.
You are testing high voltage.
You are testing high voltage.
The A28 hybrid/EV battery contactor assembly high voltage sense lead connector X5 must remain disconnected.
Hybrid Battery 1 - 80 Cell Group Diagnosis
- Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling .
- Remove the A4 hybrid/EV battery pack cover. Refer to High Voltage Battery Cover Replacement
- Disconnect the harness connector to the K112 Hybrid/EV Battery Interface Control Module at the appropriate C4 Hybrid/EV Battery Section.
- Connect the EL-48571 High Voltage Battery Pin Out Box with the EL-48571-45 Battery Pinout Box Adapter to the appropriate battery section.
- Insert the DMM probes into the EL-48571 test cavities.
- Measure and record the voltage of each of the cell groups by cycling the EL-48571 through each of the switch positions. Refer to EL-48571 High Voltage Battery Pin Out Box Reference
- Verify each cell group voltage reading is between 1.60 - 4.50V.
- If not within the specified range
Replace the appropriate C4 Hybrid/EV Battery Section.
- Go to next step: If within the specified range
- If not within the specified range
- Verify each cell group voltage reading is within 0.03V of each other.
- If greater than 0.03V
Replace the appropriate C4 hybrid/EV battery section.
- Go to next step: If 0.03V or less
- If greater than 0.03V
- Replace the appropriate K112 Hybrid/EV Battery Interface Control Module. After the repair is complete, the Clear Secured High Voltage DTCs procedure must be performed.
If a service replacement battery section is required, the replacement battery section will need to have its cell voltages balanced (matched) to the remaining battery sections with the EL-50332 Hybrid/EV Battery Service Tool. The EL-50332 connects to the replacement section(s) via alligator clamps. To facilitate connection of the alligator clamps, always install a replacement section into the C4D Hybrid/EV Battery Section 4 or C4E Hybrid/EV Battery Section 5 location. Reposition the existing C4D or C4E battery section into the location of the battery section requiring replacement as applicable.
The Hybrid/EV Battery Section Wiring Schematic in Energy Storage identify the battery section and voltage sense circuit terminal locations appropriate to each cell group and corresponding DTC.