HYBRID CONTROL SYSTEM ECU Power Source Circuit

DESCRIPTION

If the power switch is on (IG), the hybrid vehicle control ECU applies current to the MREL terminal to turn the IGCT relay on. This supplies power to the +B1 and +B2 terminals.

WIRING DIAGRAM

*a	No. 1 Engine Room Relay Block
*b	Auxiliary Battery
*c	Hybrid Vehicle Control ECU

PROCEDURE

1. CHECK HYBRID VEHICLE CONTROL ECU (+B1, +B2 VOLTAGE)

   
   

   1. Turn the power switch on (IG).

   2. 

      *a	Component with harness connected (Hybrid Vehicle Control ECU)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition A48-4 (+B1) - Body ground Power switch on (IG) 11 to 14 V A49-1 (+B2) - Body ground Power switch on (IG) 11 to 14 V

   3. Turn the power switch off.

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HYBRID VEHICLE CONTROL ECU (MREL VOLTAGE) Click here

   OK

2. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BODY GROUND)

   
   

   1. Disconnect the hybrid vehicle control ECU connector.

   2. 

      *a	Rear view of wire harness connector (to Hybrid Vehicle Control ECU)

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition F2-6 (E1) - Body ground Always Below 1 Ω F2-5 (E01) - Body ground Always Below 1 Ω F3-5 (E02) - Body ground Always Below 1 Ω F3-4 (E12) - Body ground Always Below 1 Ω

   3. Reconnect the hybrid vehicle control ECU connector.

      Result
      Proceed to OK NG

   
   

   OK

   GO TO PROBLEM SYMPTOMS TABLE Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

3. CHECK HYBRID VEHICLE CONTROL ECU (MREL VOLTAGE)

   
   

   1. Turn the power switch on (IG).

   2. 

      *a	Component with harness connected (Hybrid Vehicle Control ECU)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition A48-6 (MREL) - Body ground Power switch on (IG) 11 to 14 V

   3. Turn the power switch off.

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE HYBRID VEHICLE CONTROL ECU Click here

   OK

4. CHECK FUSE (PM-IGCT)

   
   
   1. 

      *1	No. 1 Engine Room Relay Block
      *2	PM-IGCT Fuse

      Remove the PM-IGCT fuse from the No. 1 engine room relay block.

   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition PM-IGCT fuse terminals Always Below 1 Ω

   3. Install the PM-IGCT fuse.

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK - HYBRID VEHICLE CONTROL ECU) Click here

   OK

5. CHECK FUSE (IGCT-IG)

   
   
   1. 

      *1	No. 1 Engine Room Relay Block
      *2	IGCT-IG Fuse

      Remove the IGCT-IG fuse from the No. 1 engine room relay block.

   2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition IGCT-IG fuse terminals Always Below 1 Ω

   3. Install the IGCT-IG fuse.

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK) Click here

   OK

6. INSPECT RELAY (IGCT)

   
   
   1. 

      *1	No. 1 Engine Room Relay Block
      *2	IGCT Relay

      Remove the IGCT relay from the No. 1 engine room relay block.

   2. 

      *1	IGCT Relay

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition 3 - 5 Auxiliary battery voltage not applied between terminals 1 and 2 10 kΩ or higher Auxiliary battery voltage applied between terminals 1 and 2 Below 1 Ω

   3. Install the IGCT relay.

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE RELAY (IGCT)

   OK

7. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK - HYBRID VEHICLE CONTROL ECU)

   
   

   1. Disconnect the hybrid vehicle control ECU connector.

   2. 

      *1	No. 1 Engine Room Relay Block
      *2	PM-IGCT Fuse

      Remove the PM-IGCT fuse from the No. 1 engine room relay block.

   3. Measure the resistance according to the value(s) in the table below.

      

      *1	No. 1 Engine Room Relay Block	-	-
      *a	Front view of wire harness connector (to Hybrid Vehicle Control ECU)	*b	PM-IGCT Fuse Holder

      Standard Resistance
      Tester Connection Condition Specified Condition A48-4 (+B1) - 2 (PM-IGCT fuse holder) Always Below 1 Ω A49-1 (+B2) - 2 (PM-IGCT fuse holder) Always Below 1 Ω

   4. Reconnect the hybrid vehicle control ECU connector.

   5. Install the PM-IGCT fuse.

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

8. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK)

   
   
   1. 

      *1	No. 1 Engine Room Relay Block
      *2	PM-IGCT Fuse
      *3	IGCT-IG Fuse
      *4	IGCT Relay

      Remove the IGCT-IG fuse, PM-IGCT fuse and IGCT relay from the No. 1 engine room relay block.

   2. 

      *1	No. 1 Engine Room Relay Block
      *a	PM-IGCT Fuse Holder
      *b	IGCT-IG Fuse Holder
      *c	IGCT Relay Holder

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition 3 (IGCT relay holder) - 2 (IGCT-IG fuse holder) Always Below 1 Ω 5 (IGCT relay holder) - 1 (PM-IGCT fuse holder) Always Below 1 Ω

   3. Install the IGCT-IG fuse, PM-IGCT fuse and IGCT relay.

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

9. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 1 ENGINE ROOM RELAY BLOCK)

   
   

   1. Disconnect the hybrid vehicle control ECU connector.

   2. 

      *1	No. 1 Engine Room Relay Block
      *2	IGCT Relay

      Remove the IGCT relay from the No. 1 engine room relay block.

   3. Measure the resistance according to the value(s) in the table below.

      

      *1	No. 1 Engine Room Relay Block	-	-
      *a	Rear view of wire harness connector (to Hybrid Vehicle Control ECU)	*b	IGCT Relay Holder

      Standard Resistance
      Tester Connection Condition Specified Condition A48-6 (MREL) - 1 (IGCT relay holder) Always Below 1 Ω A48-6 (MREL) or 1 (IGCT relay holder) - Body ground and other terminals Always 10 kΩ or higher

   4. Install the IGCT relay.

   5. Reconnect the hybrid vehicle control ECU connector.

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

10. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK - BODY GROUND)

    
    
    1. 

       *1	No. 1 Engine Room Relay Block
       *2	IGCT Relay

       Remove the IGCT relay from the No. 1 engine room relay block.

    2. 

       *1	No. 1 Engine Room Relay Block
       *a	IGCT Relay Holder

       Measure the resistance according to the value(s) in the table below.

       Standard Resistance
       Tester Connection Condition Specified Condition 2 (IGCT relay holder) - Body ground Always Below 1 Ω

    3. Install the IGCT relay.

       Result
       Proceed to OK NG

    
    

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

11. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK - HYBRID VEHICLE CONTROL ECU)

    
    
    1. 

       *1	No. 1 Engine Room Relay Block
       *2	PM-IGCT Fuse

       Remove the PM-IGCT fuse from the No. 1 engine room relay block.

    2. Disconnect the hybrid vehicle control ECU connector.

    3. Measure the resistance according to the value(s) in the table below.

       

       *1	No. 1 Engine Room Relay Block	-	-
       *a	Front view of wire harness connector (to Hybrid Vehicle Control ECU)	*b	PM-IGCT Fuse Holder

       Standard Resistance
       Tester Connection Condition Specified Condition A48-4 (+B1) or 2 (PM-IGCT fuse holder) - Body ground and other terminals Always 10 kΩ or higher A49-1 (+B2) or 2 (PM-IGCT fuse holder) - Body ground and other terminals Always 10 kΩ or higher

    4. Reconnect the hybrid vehicle control ECU connector.

    5. Install the PM-IGCT fuse.

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE FUSE (PM-IGCT)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

12. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK)

    
    
    1. 

       *1	No. 1 Engine Room Relay Block
       *2	PM-IGCT Fuse
       *3	IGCT-IG Fuse
       *4	IGCT Relay

       Disconnect the IGCT-IG fuse, PM-IGCT fuse and IGCT relay from the No. 1 engine room relay block.

    2. 

       *1	No. 1 Engine Room Relay Block
       *a	PM-IGCT Fuse Holder
       *b	IGCT-IG Fuse Holder
       *c	IGCT Relay Holder

       Measure the resistance according to the value(s) in the table below.

       Standard Resistance:

       Tester Connection	Condition	Specified Condition
       3 (IGCT relay holder) or 2 (IGCT-IG fuse holder) - Body ground and other terminals	Always	10 kΩ or higher
       5 (IGCT relay holder) or 1 (PM-IGCT fuse holder) - Body ground and other terminals	Always	10 kΩ or higher

    3. Install the IGCT-IG fuse, PM-IGCT fuse and IGCT relay.

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE RELAY (IGCT-IG)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

13. REPAIR OR REPLACE HARNESS OR CONNECTOR

    Result
    Proceed to NEXT

    
    

    NEXT

    REPLACE FUSE (PM-IGCT)

14. REPAIR OR REPLACE HARNESS OR CONNECTOR

    Result
    Proceed to NEXT

    
    

    NEXT

    REPLACE FUSE (IGCT-IG)