[Previous][Next]
INSPECTION PROCEDURE 16: EV system over heat (Oil cooling system)
 
 
 
 
COMMENTS ON TROUBLE SYMPTOM
The EV cooling system (oil cooling system), the cooling fan or the oil temperature thermistor is suspected.
 
 
PROBABLE CAUSES
  • Driving under high load (on an incline/high speed/towing)
  • Poor cooling while the battery is being charged with vehicle stationary
  • Insufficient, too much or deteriorated oil
  • Malfunction of the cooling fan system
  • The generator (oil temperature thermistor) fails
  • Malfunction of the EV oil cooler bypass valve (Thermostat)
  • The EV oil cooler fails (restricted/clogged fin)
  • The electric oil pump fails (abnormal delivery rate)
  • Clogged oil line, oil filter, or oil leaks
 
 
 
DIAGNOSIS
Required Special Tools
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
STEP 1. Using scan tool (M.U.T.-IIISE), check the actuator test. <PHEV-ECU>
Execute the following actuator tests:
  • Item No.3: Radiator fan relay 1 actuate
OK: The actuator test is executed but radiator fan 1 is activated.
  • Item No.4: Radiator fan relay 2 actuate
OK: The actuator test is executed but radiator fan 2 is activated.
Is the check result normal?
Go to Step 2.
Proceed to GROUP 14A - Troubleshooting, Trouble Symptom Procedure "Radiator fan and condenser fan do not operate normally (The fans do not operate or operate unintentionally)." .
 
STEP 2. Oil leak check
Refer to GROUP 14B - Oil Leak Check .
Is the check result normal?
Go to Step 3.
Repair the leakage (Refer to GROUP 14B - EV Oil Hose and EV Oil Pipe ).
 
STEP 3. Oil level check
Refer to GROUP 14B - Oil Change .
Is the check result normal?
Go to Step 4.
Adjust the oil level until it reaches the bottom of the oil level plug hole.
 
STEP 4. Check the oil temperature thermistor circuit.
(1) Disconnect the PHEV-ECU connector, and measure at the component side.
(2) Measure the resistance between the generator connector terminal THO and terminal TGO.
OK:
  • Approximately 55 to 70 kΩ [20°C (68°F)]
  • Approximately 23 to 30 kΩ [40°C (104°F)]
  • Approximately 12 to 15 kΩ [60°C (140°F)]
  • Approximately 5.5 to 6.7 kΩ [80 °C (176°F)]
Is the check result normal?
Go to Step 5.
Replace the generator (Refer to ).
 
STEP 5. EV oil hose and EV oil pipe check.
Check that the component is not clogged or damaged (Refer to GROUP 14B - Oil hose and pipe ).
Is the check result normal?
Go to Step 6.
Repair or replace a clogged or damaged component.
 
STEP 6. EV oil cooler bypass valve check.
Refer to GROUP 14B - Electric Oil Pump/EV Oil Cooler Bypass Valve, Inspection .
Is the check result normal?
Go to Step 7.
Replace the EV oil cooler bypass valve (Refer to GROUP 14B - Electric Oil Pump/EV Oil Cooler Bypass Valve ).
 
STEP 7. Using scan tool (M.U.T.-IIISE), check the actuator test. <GCU>
cautionWhen ambient temperature is -15°C or less, the oil pump may not operate stably. Execute the actuator test only when the temperature is above -15°C (5°F).
(1) Operate the electric motor switch without depressing the brake pedal and turn ON the power supply mode of electric motor switch (READY indicator does not illuminate).
(2) Execute the following actuator tests.
Item No.1. Oil pump
(3) Observe the data list below while step (2) is in progress.
Item No.32. Oil pump operating condition
OK: 26%
noteThe oil pump operating condition may fluctuate by 1%.
Is the check result normal?
Replace the EV oil cooler (Refer to GROUP 14B - EV Oil Cooler ).
Replace the electric oil pump (Refer to GROUP 14B - Electric Oil Pump/EV Oil Cooler Bypass Valve ).