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INSULATION DETERIORATION INSPECTION
 
 
caution
  • If the insulation resistance of the drive battery is measured (DC 1,000 V applied) while the cell voltage is input to the BMU, the BMU gets damaged.
  • When using the special tool electric insulation tester (MB992355), make sure to disconnect the cell voltage wiring harness from the BMU.
note
  • Do not restore removed parts unless instructed to do so, and perform the inspection while disassembling the drive battery.
  • There may be multiple parts with lowered insulation resistance. Record the faulty parts and keep inspecting until the inspection procedures are completed.
Required Special Tools:
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
  • MB992355: Electric insulation tester
 
 
 
 
1. INSULATION RESISTANCE CHECK OF SERVICE PLUG BOX
dangerMake sure to attach the battery module terminal cover except when working on the relevant part.
1. Remove the battery tray cover from the drive battery (Refer to BATTERY TRAY COVER REMOVAL AND INSTALLATION).
2. Remove the service plug box with the service plug box bus bar attached (Refer to SERVICE PLUG BOX ASSEMBLY REMOVAL AND INSTALLATION).
3. Use the special tool electric insulation tester (MB992355), and set the range to 1,000 V.
4. Measure the insulation resistance between the service plug box terminals (two parts) and ground terminal (service plug box bracket).
 
+ terminal- terminalNormal condition
Service plug box terminal (vehicle left side)Ground terminal (service plug box bracket)50 MΩ or more
Service plug box terminal (vehicle right side)Ground terminal (service plug box bracket)
  • When the resistance is normal,  go to
  • When the resistance is not normal, go to
 
 
 
2. CHECK OF SERVICE PLUG BOX BUS BAR COVERING
dangerMake sure to attach the battery module terminal cover except when working on the relevant part.
1. Remove the following bus bars from the service plug box.
  • Service plug box bus bar (A)
  • Service plug box bus bar (B)
  • Service plug box bus bar (C)
2. Check that there is no damage on each bus bar covering, and wiring harness and connector.
  • When there is no damage, record the service plug box as a faulty part. Then, go to
  • When there is damage, record the damaged bus bar, wiring harness and connector as faulty parts. Then, go to
 
 
 
3. LEAK VOLTAGE CHECK OF CELL VOLTAGE HARNESS
dangerMake sure to attach the battery module terminal cover except when working on the relevant part.
1. Using a high voltage multimeter, measure the voltage between the battery module terminals (+ terminal of No. 5, - terminal of No. 4) and ground terminal (battery upper plate).
noteAfter setting the probe, wait for enough time to measure the stable voltage.
 
+ terminal- terminalNormal condition
+ terminal of battery module No. 5 Ground terminal (battery upper plate)Approximately 0 V
- terminal of battery module No. 4Ground terminal (battery upper plate)
 
 
 
4. LEAK VOLTAGE CHECK AFTER DISCONNECTING CELL VOLTAGE WIRING HARNESS CONNECTOR
dangerMake sure to attach the battery module terminal cover except when working on the relevant part.
1. Disconnect nine connectors from the cell voltage wiring harness.
2. Using a high voltage multimeter, measure the voltage between the battery module terminals (+ terminal of No. 5, - terminal of No. 4) and ground terminal (battery upper plate).
noteWait for 1 minute or more before measuring the voltage.
 
+ terminal- terminalNormal condition
+ terminal of battery module No. 5 Ground terminal (battery upper plate)Approximately 0 V
- terminal of battery module No. 4Ground terminal (battery upper plate)
 
 
 
5. CHECK OF BATTERY MODULE BUS BAR COVERING
dangerMake sure to attach the battery module terminal cover except when working on the relevant part.
1. Remove the following bus bars.
2. Check that there is no damage on the covering of the bus bars.
  • When there is no damage, go to
  • When there is damage, record the damaged bus bars as faulty parts. Then, go to
 
 
6. LEAK VOLTAGE CHECK OF BATTERY MODULE
dangerMake sure to attach the battery module terminal cover except when working on the relevant part.
1. Polish the drive battery high voltage connector base using a file etc.
2. Using a high voltage multimeter, measure the voltage between the +/- terminal of each battery module and ground terminal (drive battery high voltage connector base).
 
+ terminal- terminalNormal condition
+ terminal of each battery moduleGround terminal (drive battery high voltage connector base)Approximately 0 V
- terminal of each battery moduleGround terminal (drive battery high voltage connector base)
  • When the voltage is normal, go to
  • When the voltage is not normal, record the battery modules as faulty parts. Then, go to
 
 
7. INSULATION RESISTANCE CHECK OF BATTERY MODULE
1. Remove the battery module which is judged as a faulty part in "LEAK VOLTAGE CHECK OF BATTERY MODULE" from the drive battery tray.
2.
cautionAs there is a risk of part failure, be careful for the measuring range, and not to measure the insulation resistance by applying DC 1,000 V.
Use the special tool electric insulation tester (MB992355), and set the range to 500 V.
3. Measure the insulation resistance between +/- terminal of the battery module and ground terminal (battery module body). After the measurement, go to
 
+ terminal- terminalNormal condition (Reference)
Battery module + terminalBattery module body
  • 10-cell battery module: 400 MΩ or more
  • 14-cell battery module: 285 MΩ or more
Battery module - terminalBattery module body
 
 
 
8. INSULATION RESISTANCE CHECK OF JUNCTION BOX NO. 2 (MODULE SIDE TERMINAL)
1. Use the special tool electric insulation tester (MB992355), and set the range to 1,000 V.
2. Polish the drive battery high voltage connector base using a file etc.
3. Measure the insulation resistance between the junction box No. 2 terminal and ground terminal (drive battery high voltage connector base).
 
+ terminal- terminalNormal condition
Junction box No. 2 terminal (to module No. 1)Ground terminal (drive battery high voltage connector base)50 MΩ or more
Junction box No. 2 terminal (to module No. 8)Ground terminal (drive battery high voltage connector base)
  • When the resistance is normal, go to
  • When the resistance is not normal, record the junction box No. 2 as a faulty part. Then, go to
 
 
 
9. INSPECTION RESULT CONFIRMATION
Confirm the faulty parts recorded in the previous procedures.
  • When there are faulty parts, replace all the recorded parts. Then, go to
  • When there is no faulty part, go to
 
 
10. LEAK VOLTAGE CHECK OF DRIVE BATTERY MODULE SYSTEM
1. Assemble the drive battery just before the battery tray cover installation (Refer to SERVICE PROCEDURE).
2. Polish the drive battery high voltage connector base using a file etc.
3. Using a high voltage multimeter, measure the voltage between the following service plug box terminals and ground terminal (drive battery high voltage connector base).
 
+ terminal- terminalNormal condition
service plug box terminal (vehicle left side)Ground terminal (drive battery high voltage connector base)Approximately 0 V
service plug box terminal (vehicle right side)Ground terminal (drive battery high voltage connector base)
  • When the voltage is normal, the inspection is complete.
  • When the voltage is not normal, go to