Hybrid Vehicle Control Ecu Assembly Power Supply System

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

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 Hybrid vehicle control ECU assembly (+ B1, +B2 VOLTAGE) .
1. Turn to IG ON.
2. Using a tester, measure the voltage between Hybrid vehicle control ECU assembly connector and chassis ground. (With the connector connected)
  Connector and terminal
  
  (i370) No. 1 (+) - Chassis ground (-):
  
  (B606) No. 2 (+) - Chassis ground (-):
  
  Is the voltage 11 - 14 V?
  
  Yes:
  
  Go to 2.
  
  No:
  
  Go to 3.
CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - CHASSIS GROUND) .
1. Turn to IG OFF.
2. Disconnect Hybrid vehicle control ECU assembly connectors (B605), (i369) and (i370).
3. Using a tester, measure the resistance between Hybrid vehicle control ECU assembly connector and chassis ground.
  Connector and terminal
  
  (B605) No. 2 - Chassis ground:
  
  (i369) No. 2 - Chassis ground:
  
  (i369) No. 6 - Chassis ground:
  
  (i370) No. 6 - Chassis ground:
  
  Is the resistance less than 1 Ω?
  
  Yes:
  
  The power supply circuit is normal.
  
  No:
  
  Repair or replace the Wire harness between Hybrid vehicle control ECU assembly connector and chassis ground.
CHECK Hybrid vehicle control ECU assembly (MREL VOLTAGE) .
1. Turn to IG ON.
2. Using a tester, measure the voltage between Hybrid vehicle control ECU assembly connector and chassis ground. (With the connector connected)
  Connector and terminal
  
  (B606) No. 1 (+) - Chassis ground (-):
  
  Is the voltage 11 - 14 V?
  
  Yes:
  
  Go to 4.
  
  No:
  
  Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .
CHECK FUSE (PM IGCT) .
1. Turn to IG OFF.
2. Remove the F/B NO. 16 FUSE from the Relay and fuse box (F/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
3. Check F/B NO. 16 FUSE.
  Is the F/B NO. 16 FUSE OK?
  
  Yes:
  
  Go to 5.
  
  No:
  
  Go to 13.
CHECK FUSE (IGCT SCENE) .
1. Remove the M/B fuse No. 5 from Main fuse box (M/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Check the M/B fuse No. 5.
  Is the M/B fuse No. 5 OK?
  
  Yes:
  
  Go to 6.
  
  No:
  
  Go to 14.
CHECK RELAY UNIT (IGCT SCENE) .
1. Remove the IGCT scene relay from the Main fuse box (M/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
2. Check IGCT scene relay.
  Is the IGCT scene relay OK?
  
  Yes:
  
  Go to 7.
  
  No:
  
  Replace IGCT scene relay.
CHECK Wire harness AND CONNECTOR (Relay and fuse box (F/B) - Hybrid vehicle control ECU assembly) .
1. Disconnect Hybrid vehicle control ECU assembly connectors (i369) and (i370).
2. Using a tester, measure the resistance between Relay and fuse box (F/B) and Hybrid vehicle control ECU assembly connector.
  Connector and terminal
  
  F/B NO. 16 FUSE - (i369) No. 4:
  
  F/B NO. 16 FUSE - (i370) No. 3:
  
  Is the resistance less than 1 Ω?
  
  Yes:
  
  Go to 8.
  
  No:
  
  Repair or replace Wire harness between Relay and fuse box (F/B) and Hybrid vehicle control ECU assembly connector.
CHECK THE Main fuse box (M/B) UNIT .
Using a tester, measure the resistance between Main fuse box (M/B) terminals.

Connector and terminal

IGCT SCENE FUSE (M/B No. 5 fuse) - IGCT scene relay terminal 1:

Is the resistance less than 1 Ω?

Yes:

Go to 9.

No:

Replace Main fuse box (M/B) (bulk Wire harness).
CHECK Wire harness AND CONNECTOR (Relay and fuse box (F/B) - Main fuse box (M/B)) (OPEN CIRCUIT) .
Using the tester, measure the resistance between Relay and fuse box (F/B) and Main fuse box (M/B).

Connector and terminal

IGCT scene relay terminal 3 - F/B NO. 16 FUSE terminal:

Is the resistance less than 1 Ω?

Yes:

Go to 10.

No:

Repair or replace the Wire harness between Relay and fuse box (F/B) and Main fuse box (M/B).
CHECK Wire harness AND CONNECTOR (Main fuse box (M/B) - Hybrid vehicle control ECU assembly) (OPEN CIRCUIT) .
Using a tester, measure the resistance between Hybrid vehicle control ECU assembly connector and Main fuse box (M/B).

Connector and terminal

IGCT scene relay terminal 2 - (B606) No. 1:

Is the resistance less than 1 Ω?

Yes:

Go to 11.

No:

Repair or replace the Wire harness between Hybrid vehicle control ECU assembly connector and Main fuse box (M/B).
CHECK Wire harness AND CONNECTOR (Main fuse box (M/B) - Hybrid vehicle control ECU assembly) (OPEN CIRCUIT) .
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

(B606) No. 6 - (B606) No. 1 - 35:

(B606) No. 6 - Chassis ground:

Is the resistance 10 kΩ or more?

Yes:

Go to 12.

No:

Repair or replace the Wire harness between Hybrid vehicle control ECU assembly connector and Main fuse box (M/B).
CHECK Wire harness AND CONNECTOR (Main fuse box (M/B) - CHASSIS GROUND) (OPEN CIRCUIT) .
Using a tester, measure the resistance between Main fuse box (M/B) and chassis ground.

Connector and terminal

IGCT scene relay terminal 4 - Chassis ground:

Is the resistance less than 1 Ω?

Yes:

The circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

NOTE: In this case, temporary poor contact of connector, or temporary open or short circuit of the Wire harness may be the cause.

No:

Repair or replace the Wire harness between Main fuse box (M/B) and chassis ground.
CHECK Wire harness AND CONNECTOR (Relay and fuse box (F/B) - Hybrid vehicle control ECU assembly) (SHORT TO GROUND) .
1. Disconnect Hybrid vehicle control ECU assembly connector (i369).
2. 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
  
  (i369) No. 4 - (i369) No. 1 - 35:
  
  (i369) No. 4 - Chassis ground:
  
  (i370) No. 3 - (i370) No. 1 - 31:
  
  (i369) No. 3 - Chassis ground:
  
  Is the resistance 10 kΩ or more?
  
  Yes:
  
  Replace F/B NO. 16 FUSE. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
  
  No:
  
  Repair or replace Wire harness between Relay and fuse box (F/B) and Hybrid vehicle control ECU assembly connector, and replace F/B NO. 16 FUSE. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
CHECK Wire harness AND CONNECTOR (Relay and fuse box (F/B) - Main fuse box (M/B)) (SHORT TO GROUND) .
Using a tester, measure the resistance between Main fuse box (M/B) terminals and between Main fuse box (M/B) and chassis ground.

Connector and terminal

IGCT scene relay terminal 1 - IGCT scene relay terminal 1 - 4:

IGCT scene relay terminal 1 - Chassis ground:

IGCT scene relay terminal 3 - IGCT scene relay terminal 1 - 4:

IGCT scene relay terminal 3 - Chassis ground:

Is the resistance 10 kΩ or more?

Yes:

Replace IGCT SCENE FUSE. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .

No:

Repair or replace Wire harness between Relay and fuse box (F/B) and Main fuse box (M/B), and replace IGCT SCENE FUSE. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .