DTC P314A-31: Motor Electronics Coolant Pump "A" No Signal: Notes

WARNING: This page is about a different variant/trim than selected.

1. -

Outline of diagnosis:

With READY ON, revolution speed of Inverter water pump is not transmitted to Hybrid vehicle control ECU assembly

Connection fault of +B or revolution speed signal line to Inverter water pump
Power supply circuit fault in Inverter water pump, or Hybrid vehicle control ECU assembly

(1 trip detection logic)

Trouble symptom:

Normal driving

Wiring diagram:

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

Courtesy of SUBARU OF AMERICA, INC.

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

Courtesy of SUBARU OF AMERICA, INC.

Courtesy of SUBARU OF AMERICA, INC.

Courtesy of SUBARU OF AMERICA, INC.

Courtesy of SUBARU OF AMERICA, INC.

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, perform the clear memory of [P-HEV Hybrid Powertrain Control]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
2. 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
3. With the active test [Activate the Inverter Water Pump] being performed, check that Inverter water pump is operating (vibrating).
Is Inverter water pump operating?

Yes : Go to 2.

No : Go to 8.
CHECK CONNECTION CONDITION OF CONNECTOR (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 or 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 3.
CHECK CONNECTION CONDITION OF CONNECTOR (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 4.
CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter water pump) (OPEN CIRCUIT) .
1. Turn the ignition to OFF.
2. Disconnect Hybrid vehicle control ECU assembly connector (B606).
3. Disconnect the Inverter water pump connector A7.
4. Using a tester, measure the resistance between Hybrid vehicle control ECU assembly connector and Inverter water pump connector.
  Connector & terminal
  
  (B606) No. 10 - (B659) No. 2:
Is the resistance less than 1 Ω?

Yes : Go to 5.

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 OR LINE-TO-LINE SHORT) .
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 & terminal

(B606) No. 10 - (B606) No. 1 - 35:

(B606) No. 10 - Chassis ground:

Is the resistance 10 kΩ or more?

Yes : Go to 6.

No : Repair or replace the Wire harness between Hybrid vehicle control ECU assembly connector and Inverter water pump connector.
CHECK Hybrid vehicle control ECU assembly .
1. Connect the connector (B606) of Hybrid vehicle control ECU assembly.
2. Turn to IG ON.
3. Using a tester, measure the voltage between Hybrid vehicle control ECU assembly connector terminals.
  Connector & terminal
  
  (B606) No. 10 (+) - (i369) No. 6 (-):
Is the voltage 11 - 14 V?

Yes : Go to 7.

No : Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

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).

Using the Subaru Select Monitor, perform the clear memory of [P-HEV Hybrid Powertrain Control]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
Restore the vehicle to its original state.
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

Using an oscilloscope, measure the waveform between Hybrid vehicle control ECU assembly connector terminals. (With the connector connected)

Connector & terminal

(B606) No. 10 - (i369) No. 6:

Gauge set: 5 V/DIV, 50 ms/DIV

Measuring condition:

IG ON
Active test Activate the Inverter Water Pump being performed

Courtesy of SUBARU OF AMERICA, INC.

Is the waveform cycle 300 ms or less?

Yes : Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

No : Replace Inverter water pump. Ref. to COOLING (H4DO (HEV))>INVERTER WATER PUMP .

CHECK CONNECTION CONDITION OF CONNECTOR (Inverter water pump CONNECTOR) .
Check the connecting condition of connector in Inverter water pump and check the relevant terminals for contact pressure, deformation and intrusion of water or foreign matter. 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 : Go to 11.

No : Go to 9.
CHECK Wire harness AND CONNECTOR (Inverter water pump - IGCT IG relay) .
1. Remove the IGCT IG relay from the Relay holder. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Disconnect Inverter water pump connector (B659).
3. Using a tester, measure the resistance between Inverter water pump connector and IGCT IG relay terminals.
  Connector & terminal
  
  (B659) No. 1 - (B225) No. 33:
Is the resistance less than 1 Ω?

Yes : Go to 10.

No : Go to 12.
CHECK Wire harness AND CONNECTOR (Inverter water pump - CHASSIS GROUND) .
1. Attach the IGCT IG relay. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Using a tester, measure the resistance between Inverter water pump connector and chassis ground.
  Connector & terminal
  
  (B659) No. 3 - Chassis ground:
Is the resistance less than 1 Ω?

Yes : Replace Inverter water pump. Ref. to COOLING (H4DO (HEV))>INVERTER WATER PUMP .

No : Repair or replace Wire harness between Inverter water pump connector and chassis ground.
CHECK FUSE (INV W/PMP) .
1. Remove the Inverter water pump fuse from the Relay & fuse box (F/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Check Inverter water pump fuse.
Is the fuse OK?

Yes : Connect the Inverter water pump connector securely.

No : Connect the Inverter water pump connector securely, and replace Inverter water pump fuse.
CHECK INSTALLATION CONDITION (Inverter water pump fuse) .
Check installation condition of Inverter water pump fuse.

Is Inverter water pump fuse securely installed?

Yes : Go to 13.

No : Go to 16.
CHECK Wire harness AND CONNECTOR (Inverter water pump CIRCUIT) (OPEN CIRCUIT) .
1. Remove the Inverter water pump fuse from the Relay & fuse box (F/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Remove the IGCT IG relay from the Relay holder. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
3. Disconnect Inverter water pump connector (B659).
4. Using a tester, measure the resistance between Inverter water pump connector and Inverter water pump fuse, and between IGCT IG relay terminal and Inverter water pump fuse.
  Connector & terminal
  
  Inverter water pump fuse terminal 2 - A7-4 (+BWP):
  
  Inverter water pump fuse terminal 1 - IGCT IG relay terminal 5:
  
  (B659) No. 1 - (i137) No. 5:
  
  (B159) No. 1 - (B225) No. 33:
Is the resistance less than 1 Ω?

Yes : Go to 14.

No : Repair or replace Wire harness between Inverter water pump connector and Inverter water pump fuse, or between IGCT IG relay and Inverter water pump fuse.
CHECK Wire harness AND CONNECTOR (Inverter water pump CIRCUIT) (SHORT TO GROUND OR LINE-TO-LINE SHORT) .
Using a tester, measure the resistance between terminals in Inverter water pump connector, and between Inverter water pump connector and chassis ground.

Connector & terminal

A7-4 (+BWP) - between other terminals and chassis ground:

(B659) No. 1 - (B659) No. 1 - 4:

(B659) No. 1 - Chassis ground:

Is the resistance 10 kΩ or more?

Yes : Go to 15.

No : Go to 18.
CHECK FUSE (INV W/PMP) .
1. Remove the Inverter water pump fuse from the Relay & fuse box (F/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Check Inverter water pump fuse.
Is the fuse OK?

Yes : Repair or replace the installation terminal of Inverter water pump fuse.

No : Go to 19.
CHECK INSTALLATION TERMINAL (Inverter water pump fuse) .
Check the installation terminal of Inverter water pump fuse.

Is there bend, looseness or corrosion in the installation terminal of Inverter water pump fuse?

Yes : Go to 21.

No : Go to 17.
CHECK FUSE (INV W/PMP) .
1. Remove the Inverter water pump fuse from the Relay & fuse box (F/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Check Inverter water pump fuse.
Is the fuse OK?

Yes : Install the fuse securely.

No : Replace the fuse.
CHECK FUSE (INV W/PMP) .
1. Remove the Inverter water pump fuse from the Relay & fuse box (F/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Check Inverter water pump fuse.
Is the fuse OK?

Yes : Repair or replace Wire harness.

No : Go to 19.
CHECK Wire harness AND CONNECTOR (Inverter water pump - CHASSIS GROUND) (OPEN CIRCUIT) .
1. Attach the Inverter water pump fuse. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Disconnect Inverter water pump connector (B659).
3. Using a tester, measure the resistance between Inverter water pump connector and chassis ground.
  Connector & terminal
  
  (B659) No. 3 - Chassis ground:
Is the resistance less than 1 Ω?

Yes : Go to 20.

No : Repair or replace Wire harness between Inverter water pump connector and chassis ground and the installation terminal of Inverter water pump fuse, and replace Inverter water pump fuse.
CHECK INSTALLATION TERMINAL (Inverter water pump fuse) .
Check the installation terminal of Inverter water pump fuse. Ref. to COOLING (H4DO (HEV))>INVERTER WATER PUMP .

Is there bend, looseness or corrosion in the installation terminal of Inverter water pump fuse?

Yes : Replace Inverter water pump and Inverter water pump fuse. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .

No : Repair or replace the installation terminal of Inverter water pump fuse, and replace Inverter water pump fuse.
CHECK FUSE (INV W/PMP) .
1. Remove the Inverter water pump fuse from the Relay & fuse box (F/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Check Inverter water pump fuse.
Is the fuse OK?

Yes : Repair or replace the installation terminal of Inverter water pump fuse.

No : Repair or replace the installation terminal of Inverter water pump fuse, and replace Inverter water pump fuse.