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DTC P1A1B: Electric motor drive voltage too low
 
 
danger
  • When servicing the high voltage system parts, always shut off the high voltage by removing the service plug (Refer to ).
  • When servicing the high voltage system parts, always wear the protective equipment or armor to measure the high voltage (Refer to ).
 
 
MONITOR EXECUTION
  • Continuous
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Drive motor inverter voltage sensor
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
  • The vehicle status is propulsion system active.
Judgment Criterion
  • Change of the inverter voltage is less than 200 volts (2.405 volts) for 0.5 second.
 
 
OBD-II DRIVE CYCLE PATTERN
  • Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
 
 
PROBABLE CAUSES
  • The battery pack fails
  • The high-voltage circuit fails
  • Malfunction of the power drive unit (FEMCU)
 
 
DIAGNOSIS
Required Special Tools
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
STEP 1. Using scan tool (M.U.T.-IIISE), check whether the other DTC is set.
Check if DTC P1037 is set in the REMCU.
Is the DTC set?
Go to Step 2.
Go to Step 6.
 
STEP 2. Check the high-voltage fuse.
danger
  • Carry out the check on the high-voltage circuit while reading carefully the precautions on handling a high-voltage vehicle.
  • Wear the specified protection equipment during the check.
Check the high-voltage fuse (Refer to GROUP 54Dc - On-vehicle Service ).
Is the check result normal?
Go to Step 3.
Engage the high-voltage fuse securely, or replace it (Refer to Refer to GROUP 54Dc - On-vehicle service ). Then go to Step 9 .
 
STEP 3. Check the high-voltage circuit.
danger
  • Carry out the check on the high-voltage circuit while reading carefully the precautions on handling a high-voltage vehicle.
  • Wear the specified protection equipment during the check.
Check whether the high-voltage wiring harness is connect securely or damaged.
Is the check result normal?
Go to Step 4.
Reconnect the high-voltage wiring harness. Then go to Step 9.
 
STEP 4. Check the high-voltage circuit.
danger
  • Carry out the check on the high-voltage circuit while reading carefully the precautions on handling a high-voltage vehicle.
  • Wear the specified protection equipment during the check.
(1) Remove the service plug (Refer to ).
(2) Apply a voltage of 12 V to the CNT- terminal to turn on the charging contactor.
(3) Connect a high-voltage compatible multimeter between the main drive lithium-ion battery high-voltage terminal (REMCU) and the main drive lithium-ion battery service plug rear terminal.
OK: Approximately 100 - 164 V

(4) Apply a voltage of 12 V to the CNTP terminal to turn on the charging contactor.
(5) Connect a high-voltage compatible multimeter between the main drive lithium-ion battery high-voltage terminal (REMCU) and the main drive lithium-ion battery service plug front terminal.
OK: Approximately 100 - 164 V

(6) Apply a voltage of 12 V to the CNT+ terminal to turn on the charging contactor.
(7) Connect a high-voltage compatible multimeter between the main drive lithium-ion battery high-voltage terminal (REMCU) and the main drive lithium-ion battery service plug front terminal.
OK: Approximately 100 - 164 V
Is the check result normal?
Go to Step 8.
Go to Step 5.
 
STEP 5. Check the high-voltage wiring harness and bus bar in the main drive lithium-ion battery.
(1) Remove the battery tray cover (Refer to GROUP 54Dc - Main Drive Lithium-ion Battery Disassembly and Assembly ).
(2) Check the high-voltage wiring harness and bus bar in the main drive lithium-ion battery for looseness or damage.
Is the check result normal?
Replace the power drive unit (Refer to ). Then assemble the main drive lithium-ion battery assembly (Refer to GROUP 54Dc - Main Drive Lithium-ion Battery Disassembly and Assembly ). Then go to Step 9.
Repair the connector(s) or wiring harness. Then go to Step 9.
 
STEP 6. Check the high-voltage terminal.
danger
  • Carry out the check on the high-voltage circuit while reading carefully the precautions on handling a high-voltage vehicle.
  • Wear the specified protection equipment during the check.
Check that the following cable is tightened to the specified torque.
  • Main drive lithium-ion battery front cable (P, N line) connection (power drive unit side) (Refer to ).
Is the check result normal?
Go to Step 7.
Tighten the main drive lithium-ion battery front cable (P, N line) to the specified torque (power drive unit side) (Refer to ). Then go to Step 9.
 
STEP 7. Check the high-voltage circuit.
danger
  • Carry out the check on the high-voltage circuit while reading carefully the precautions on handling a high-voltage vehicle.
  • Wear the specified protection equipment during the check.
(1) Check that the following cable is tightened to the specified torque.
  • Main drive lithium-ion battery front cable (P, N line) connection (main drive lithium-ion battery assembly side) (Refer to GROUP 54Dc - Main Drive Lithium-ion Battery ).
(2) Check if the main drive lithium-ion battery front cable (P, N line) is damaged.
Is the check result normal?
Go to Step 8.
: Tighten the main drive lithium-ion battery front cable (P, N line) to the specified torque (main drive lithium-ion battery assembly side) (Refer to GROUP 54Dc - Main Drive Lithium-ion Battery ). Then go to Step 9.
: Replace the main drive lithium-ion battery front cable (P, N line) (Refer to <Power drive unit side> and GROUP 54Dc - Main Drive Lithium-ion Battery <Main drive lithium-ion battery assembly side>). Then go to Step 9.
 
STEP 8. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to OBD-II Drive Cycle - Pattern 1 .
(2) Check the DTC.
Is the DTC set?
Replace the power drive unit (Refer to ). Then go to Step 9.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
 
STEP 9. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
(2) Check the DTC.
Is the DTC set?
Retry the troubleshooting.
The inspection is complete.