Cooling System

CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .

Wiring diagram:

Hybrid system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>HYBRID ELECTRIC VEHICLE SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CHECK VEHICLE CONDITION .
Ask the customer about the following items.
- Ask if the front surface of the radiator grille is blocked with some sort of cover.
- Ask if a cover was attached on the radiator grille before.
Is a cover attached, or was a cover attached before?

Yes:

Explain to the customer and remove the cover.

NOTE: When the radiator grille is blocked, temperature of the inverter coolant may increase and a malfunction may be detected.

No:

Go to 2.
CHECK AMOUNT OF COOLANT .
Check that the coolant is filled up to the Low level or more in the inverter reservoir tank assembly, and that the coolant is not leaking.

Is it true that there is no coolant leakage and, as the same time, the coolant in the inverter reservoir tank assembly is at Low level or more?

Yes:

Go to 3.

No:

Repair the coolant leakage. Or, add the coolant.
CHECK COOLANT SYSTEM HOSE .
Check the coolant hose for bends and clogging.

Are there bends or clogging?

Yes:

Repair or replace the coolant system hose.

No:

Go to 4.
PERFORM ACTIVE TEST (Radiator Fan Relay) .
1. Using the Subaru Select Monitor, select the following items in the [Active Test] of [Engine Control System]. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>ACTIVE TEST .
  - Active test item: Radiator Fan Relay
2. With [Radiator Fan Relay] ON, check the cooling fan condition.
  When the cooling fan is rotating according to the active test, go to A.
  
  When the cooling fan does not rotate, go to B.
  
  When the cooling fan does not stop rotating, go to B.
  
  Yes:
  1. Go to 5.
  2. Check Cooling fan system. Ref. to COOLING (H4DO(HEV))>RADIATOR FAN SYSTEM .
  No:
  
  -
PERFORM ACTIVE TEST (Active Grille Shutter Control) .
1. Using the Subaru Select Monitor, select the following items in the [Active Test] of [Engine Control System]. Ref. to ENGINE (DIAGNOSTICS) (H4DO(HEV))>ACTIVE TEST .
  - Active test item: Active Grille Shutter Control
2. Check if the active grille shutter operates according to the operation of the active test [Active Grille Shutter Control].
  Does the active grille shutter operate according to the operation?
  
  Yes:
  
  Go to 6.
  
  No:
  
  Check the grille shutter. Ref. to COOLING (H4DO(HEV))>ACTIVE GRILLE SHUTTER .
PERFORM ACTIVE TEST (Inverter water pump) .
NOTE:
- Check that coolant water is filled up to the Low level or more in the inverter reservoir tank assembly.
- Inverter water pump may stop due to Battery (12V) voltage decrease. Therefore, be sure to perform the inspection with Battery (12V) voltage at 11 V or more.
- Perform the inspection when the inverter coolant temperature is at -15 - 65°C (5 - 149°F).
1. Using the Subaru Select Monitor, select the following items in the [Active Test] of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>ACTIVE TEST .
  - Active test item: Activate the Inverter Water Pump
  - Signal selection: Inverter Water Pump Revolution
2. With the active test [Activate the Inverter Water Pump] being performed, check [Data Monitor] for [Inverter Water Pump Revolution].
  Is the data 2500 - 5850 rpm?
  
  NOTE: While Inverter water pump is stopping, the Inverter water pump revolution speed becomes less than 176 rpm.
  
  Yes:
  
  Go to 7.
  
  No:
  
  Go to 9.
CHECK DATA MONITOR .
Using the Subaru Select Monitor, display the following items in the [Data Monitor] of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DATA MONITOR .
- Generator Inverter Calculated Temperature
- Motor Inverter Temperature
- Boosting Converter Temperature (Upper)
- Boosting Converter Temperature (Lower)
- Inverter Coolant Water Temperature
Is the difference between [Inverter Coolant Water Temperature] and the displayed temperature of other [Data Monitor] item less than 20°C (68°F)?

Yes:

Go to 8.

No:

Replace Inverter with converter assembly. Ref. to HYBRID ELECTRIC VEHICLE>INVERTER AND CONVERTER ASSEMBLY .
CHECK DATA MONITOR .
Using the Subaru Select Monitor, display the following items in the [Data Monitor] of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DATA MONITOR .
- Ambient Temperature
Is [Ambient Temperature] higher than the freezing temperature of SUBARU Super Coolant?

NOTE: The SUBARU Super Coolant with 50% concentration freezes at -36°C (-33°F). Ref. to COOLING (H4DO(HEV))>GENERAL DESCRIPTION .

Yes:

Cooling System is normal.

No:

Replace the coolant. Ref. to COOLING (H4DO(HEV))>ENGINE COOLANT .
NOTE:
- The SUBARU Super Coolant does not circulate when frozen. As a result, coolant temperature in Inverter with converter assembly may increase and a malfunction may be detected.
- Malfunctions are also detected, when Inverter water pump cannot rotate due to the SUBARU Super Coolant being frozen.
- When a malfunction is detected due to the SUBARU Super Coolant being frozen, reproduction of the fault is impossible. Therefore, judge possibility of freeze from the replacement history of the SUBARU Super Coolant and the ambient temperature at the time of malfunction detection.
CHECK CONNECTOR CONNECTION CONDITION (Hybrid vehicle control ECU assembly CONNECTOR) .
Check the connecting condition of connectors (B606) and (i369) in Hybrid vehicle control ECU assembly and check the relevant terminals for contact pressure, deformation and intrusion of water and foreign matter. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

Is there looseness at the connector connection, or any poor contact, deformation or intrusion of water or foreign matters at the relevant terminals?

Yes:

Connect the connector securely. Or repair the poor contact of connector.

No:

Go to 10.
CHECK CONNECTOR CONNECTION CONDITION (Inverter water pump CONNECTOR) .
Check the connecting condition of connector (B659) in Inverter water pump and check the relevant terminals for contact pressure, deformation and intrusion of water or foreign matters. Ref. to COOLING (H4DO(HEV))>INVERTER WATER PUMP .

Is there looseness at the connector connection, or any poor contact, deformation or intrusion of water or foreign matters at the relevant terminals?

Yes:

Connect the connector securely. Or repair the poor contact of connector.

No:

Go to 11.
CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter water pump) (OPEN CIRCUIT) .
1. Disconnect Hybrid vehicle control ECU assembly connector (B606).
2. Disconnect Inverter water pump connector (B659).
3. Using a tester, measure the resistance between Hybrid vehicle control ECU assembly connector and Inverter water pump connector.
  Connector and terminal
  
  (B606) No. 9 - (B659) No. 4:
  
  Is the resistance less than 1 Ω?
  
  Yes:
  
  Go to 12.
  
  No:
  
  Repair or replace the Wire harness between Hybrid vehicle control ECU assembly connector and Inverter water pump connector.
CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter water pump) (SHORT TO GROUND) .
Using a tester, measure the resistance between terminals in Hybrid vehicle control ECU assembly connector, and between Hybrid vehicle control ECU assembly connector and chassis ground.

Connector and terminal

A41-34 (IWP) - between other terminals and chassis ground:

(B606) No. 9 - (B606) No. 1 - 35:

(B606) No. 9 - Chassis ground:

Is the resistance 10 kΩ or more?

Yes:

Go to 13.

No:

Repair or replace the Wire harness between Hybrid vehicle control ECU assembly connector and Inverter water pump connector.
CHECK DATA MONITOR (Inverter water pump REVOLUTION SPEED) .
NOTE: Inverter water pump may stop due to Battery (12V) voltage decrease. Therefore, be sure to perform the inspection with Battery (12V) voltage at 11 V or more.
1. Remove the Inverter water pump fuse from the Relay and fuse box (F/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Turn to IG ON.
3. Using the Subaru Select Monitor, display the following items in the [Data Monitor] of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DATA MONITOR .
  - Inverter Water Pump Revolution
  Is the data less than 176 rpm?
  
  Yes:
  
  Go to 14.
  
  No:
  
  Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .
CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter water pump) .
1. Turn to IG OFF.
2. Install Inverter water pump fuse to Relay and fuse box (F/B).
3. Remove the IGCT IG relay from the Relay holder. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
4. Short between terminals 32 - 33 of IGCT IG relay.
5. Using a tester, measure the voltage between Hybrid vehicle control ECU assembly connector (B606 (with the connector not connected)) and Hybrid vehicle control ECU assembly connector (i369 (with the connector connected)).
  Connector and terminal
  
  (B606) No. 9 (+) (with the connector not connected (vehicle Wire harness side)) - (i369) No. 6 (-) (with the connector connected):
  
  Is the voltage 11 - 14 V?
  
  Yes:
  
  Go to 15.
  
  No:
  
  Replace Inverter water pump. Ref. to COOLING (H4DO(HEV))>INVERTER WATER PUMP .
CHECK Hybrid vehicle control ECU assembly (WAVEFORM MEASUREMENT) .
1. Install the removed relay.
2. Connect the disconnected connectors.
3. Turn to IG ON.
4. Using an oscilloscope, measure the waveform between Hybrid vehicle control ECU assembly connector terminals. (With the connector connected)
  Connector and terminal
  
  (B606) No. 9 - (i369) No. 6:
  
  Gauge set: 5 V/DIV, 50 ms/DIV
  
  Measuring condition: IG ON
  
  Is the duty ratio of waveform 3 - 9 %?
  
  Yes:
  
  Replace Inverter water pump. Ref. to COOLING (H4DO(HEV))>INVERTER WATER PUMP .
  
  No:
  
  Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .