Circuit/System Testing
- 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.
- 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.
- Vehicle OFF. Remove the G37 Hybrid/EV Battery Pack Coolant Pump fuse. Set the vehicle Charge Mode to IMMEDIATE. Connect the charge cord set. Vehicle in Service Mode.
- Verify the scan tool Hybrid/EV Battery Pack Coolant Temperature Sensor parameter increases 2.75°C (4.9°F) within 120 s when commanding the hybrid/EV battery pack coolant heater ON with a scan tool.
- If the Hybrid/EV Battery Pack Coolant Temperature Sensor did not increase
- Install the G37 Hybrid/EV Battery Pack Coolant Pump fuse. Disable the high voltage system for servicing the T24 Battery Charger and the A4 Battery Pack. Refer to High Voltage Disabling .
- Disconnect the T24 battery charger X7 connector and the A4 battery pack X4 connector.
- Inspect all connector ends for evidence of poor terminal contact and/or arc flash damage.
- If a terminal concern is observed, replace all affected components.
- Go to next step: If a terminal concern is not observed
- Test the following HV harness terminals for less than 2 Ω end to end:
- X7-A to X4-A
- X7-B to X4-B
- If greater than 2 Ω, replace the HV Bat Pos & Neg (300V) Cable.
- Go to next step: If less than 2 Ω
- Remove and open the A4 Battery Pack. Refer to Battery Upper Cover Replacement
. Inspect for any of the following INTERNAL concerns:
- Drive motor battery charger cable for loose/damaged terminal fasteners
- High voltage battery disconnect relay fuse for loose/damaged fasteners or an open fuse condition
- If a terminal concern is found, replace all affected components.
- If an open fuse condition is found, replace the fuse, the T18 Battery Charger and the K1 14V Power Module.
- If no internal concerns are observed, replace the A28 Hybrid/EV Battery Contactor Assembly.
- Go to next step: If the Hybrid/EV Battery Pack Coolant Temperature Sensor did increase
- Install the G37 Hybrid/EV Battery Pack Coolant Pump fuse. Disable the high voltage system for servicing the T18 Battery Charger, K1 14V Power Module and the T24 Battery Charger-DC. Refer to High Voltage Disabling .
- Disconnect the X3 connector at the T18 Battery Charger, the X1 connector at the K1 14V Power Module and the X6 connector at the T24 Battery Charger-DC.
- Verify that all HV harness connector and the mating module connector terminals are free from moisture, corrosion, and arc flash damage.
- If any terminals show signs of damage
Replace the HV wiring harness and affected modules as necessary.
- Go to next step: If no arc flash damage, moisture, or corrosion is found
- If any terminals show signs of damage
- Test the following HV harness terminals for less than 2 Ω end to end:
- X6-A to X1-B
- X6-A to X3-1
- X6-B to X1-A
- X6-B to X3-2
- If greater than 2 Ω
Replace the HV wiring harness.
- Go to next step: If less than 2 Ω
- Replace the T18 Battery Charger.
WARNING:
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:
Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:
Failure to follow the procedures may result in serious injury or death.
NOTE:
Do not command the heater ON any longer than is necessary to confirm the heater has high voltage and is functioning.