ECU Power Source Circuit

HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM: ECU Power Source Circuit
- ECU Power Source Circuit

DESCRIPTION

When the power switch is turned on (IG), current flows from the MREL terminal of the power management control ECU to the IGCT relay. This closes the IGCT relay contact points and supplies power to the +B1 and +B2 terminals of the power management control ECU.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK POWER MANAGEMENT CONTROL ECU (+B1, +B2 VOLTAGE)

(a) Turn the power switch on (IG).

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





Standard Voltage:





Text in Illustration





(c) Turn the power switch off.

NG -- CHECK POWER MANAGEMENT CONTROL ECU (MREL VOLTAGE)
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - BODY GROUND)

(a) Disconnect connector L5 and L6 from the power management control ECU.

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





Standard Resistance:





Text in Illustration





(c) Connect the power management control ECU connectors.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- GO TO PROBLEM SYMPTOMS TABLE Problem Symptoms Table

3. CHECK POWER MANAGEMENT CONTROL ECU (MREL VOLTAGE)

(a) Turn the power switch on (IG).

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





Standard Voltage:





Text in Illustration





NG -- REPLACE POWER MANAGEMENT CONTROL ECU Components
OK -- Continue to next step.

4. CHECK FUSE (IGCT NO. 2) P0A08

NG -- CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)
OK -- Continue to next step.

5. CHECK FUSE (IGCT) P0A08

NG -- CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (IGCT FUSE - IGCT NO. 2 FUSE))
OK -- Continue to next step.

6. INSPECT RELAY (IGCT)

(a) Remove the IGCT relay from the engine room relay block and junction block assembly.

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





Standard Resistance:





Text in Illustration





(c) Install the IGCT relay.

NG -- REPLACE RELAY (IGCT)
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)

(a) Remove the IGCT No. 2 fuse from the engine room relay block and junction block assembly.





Text in Illustration





(b) Disconnect connector A21 and A22 from the power management control ECU.

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





Text in Illustration





Standard Resistance:





(d) Install the IGCT No. 2 fuse.

(e) Connect the power management control ECU connectors.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (IGCT RELAY - IGCT FUSE))

(a) Remove the IGCT fuse from the engine room relay block and junction block assembly.





Text in Illustration





(b) Remove the IGCT relay from the engine room relay block and junction block assembly.

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





Standard Resistance:





Text in Illustration





(d) Install the IGCT fuse.

(e) Install the IGCT relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

9. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)

(a) Remove the IGCT relay from the engine room relay block and junction block assembly.

(b) Disconnect connector A22 from the power management control ECU.

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





Text in Illustration





Standard Resistance:





(d) Install the IGCT relay.

(e) Connect the power management control ECU connectors.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

10. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY - BODY GROUND)

(a) Remove the IGCT relay from the engine room relay block and junction block assembly.

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





Standard Resistance:





Text in Illustration





(c) Install the IGCT relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- CHECK FOR INTERMITTENT PROBLEMS Check for Intermittent Problems

11. CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)

CAUTION:
Be sure to wear insulated gloves.

(a) Check that the service plug grip is not installed.

NOTICE:
After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

(b) Disconnect connector A59 from the inverter with converter assembly.

(c) Disconnect connector A23 from the transmission control ECU assembly.

(d) Remove the No. 1 hybrid vehicle battery carrier bracket sub-assembly Removal.

(e) Disconnect connector c1 from the battery smart unit.

(f) Remove the IGCT No. 2 fuse from the engine room relay block and junction block assembly.





Text in Illustration





(g) Disconnect connector A21 and A22 from the power management control ECU.

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





Text in Illustration





Standard Resistance:





(i) Install the IGCT No. 2 fuse.

(j) Connect the power management control ECU connectors.

(k) Connect the battery smart unit connector.

(l) Install the No. 1 hybrid vehicle battery carrier bracket sub-assembly.

(m) Connect the transmission control ECU assembly connector.

(n) Connect the inverter with converter assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE FUSE (IGCT NO. 2)

12. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (IGCT FUSE - IGCT NO. 2 FUSE))

(a) Remove the IGCT fuse, IGCT No. 2 fuse, IGCT No. 3 fuse and PCU fuse from the engine room relay block and junction block assembly.





Text in Illustration





(b) Remove the IGCT relay from the engine room relay block and junction block assembly.

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





Standard Resistance:





Text in Illustration





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





Standard Resistance:





Text in Illustration





(e) Install the IGCT fuse, IGCT No. 2 fuse, IGCT No. 3 fuse and PCU fuse.

(f) Install the IGCT relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE FUSE (IGCT)

13. REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT -- REPLACE FUSE (IGCT NO. 2)

14. REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT -- REPLACE FUSE (IGCT)