Lexus ES manuals

Lexus ES: ECU Power Source Circuit

Lexus ES (XZ10) Service Manual / Engine & Hybrid System / Hybrid / Battery Control / Hybrid Battery System (for Lithium-ion Battery) / ECU Power Source Circuit

DESCRIPTION

If the power switch is on (IG), the battery ECU assembly applies current to the MREL terminal to turn the IGCT relay on. This supplies power to the IGCT terminals.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

  • Before the following operations are conducted, take precautions to prevent electric shock by turning the power switch off, wearing insulated gloves, and removing the service plug grip from HV battery.
    • Inspecting the high-voltage system
    • Disconnecting the low voltage connector of the inverter with converter assembly
    • Disconnecting the low voltage connector of the HV battery
  • To prevent electric shock, make sure to remove the service plug grip to cut off the high voltage circuit before servicing the vehicle.
  • After removing the service plug grip from the HV battery, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
  • After removing the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.

    *a

    Without waiting for 10 minutes

    Click here

    HINT:

    Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

  • Make sure to insulate the high-voltage connectors and terminals of the HV battery with insulating tape after removing it.

    If the HV battery stored without insulating the connectors and terminals, electric shock or fire may result.

NOTICE:

After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

Click here

PROCEDURE

1.

CHECK BATTERY ECU ASSEMBLY (IGCT VOLTAGE)

CAUTION:

Be sure to wear insulated gloves and protective goggles.

(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) Remove the No. 1 HV battery hose.

Click here

(c) Disconnect the y16 battery ECU assembly connector.

NOTICE:

Before disconnecting the connector, check that it is not loose or disconnected.

(d) Connect the cable to the negative (-) auxiliary battery terminal.

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

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

y16-13 (IGCT) - Body ground

Power switch on (IG)

11 to 14 V

NOTICE:

  • Turning the power switch on (IG) with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.
  • If the power switch is turned on (IG) with the connectors disconnected, other DTCs will be stored. Be sure to clear the DTCs after the inspection.

*a

Front view of wire harness connector

(to Battery ECU Assembly)

(g) Turn the power switch off.

(h) Disconnect the cable from the negative (-) auxiliary battery terminal.

(i) Reconnect the y16 battery ECU assembly connector.

(j) Install the No. 1 HV battery hose.

NG

GO TO STEP 3

OK

2.

CHECK HARNESS AND CONNECTOR (BATTERY ECU ASSEMBLY - BODY GROUND)

CAUTION:

Be sure to wear insulated gloves and protective goggles.

(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) Remove the No. 1 HV battery hose.

Click here

(c) Disconnect the y16 battery ECU assembly connector.

NOTICE:

Before disconnecting the connector, check that it is not loose or disconnected.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

y16-27 (GND) - Body ground

Always

Below 1 Ω

y16-3 (GND1) - Body ground

Always

Below 1 Ω

y16-4 (ERTH) - Body ground

Always

Below 1 Ω

*a

Front view of wire harness connector

(to Battery ECU Assembly)

(e) Reconnect the y16 battery ECU assembly connector.

(f) Install the No. 1 HV battery hose.

OK

GO TO PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.

CHECK FUSE (IGCT NO. 2)

(a) Remove the IGCT NO. 2 fuse from the No. 4 relay block.

*1

No. 4 Relay Block

*2

IGCT NO. 2 Fuse

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

IGCT NO. 2 fuse

Always

Below 1 Ω

(c) Install the IGCT NO. 2 fuse.

NG

GO TO STEP 6

OK

4.

CHECK HARNESS AND CONNECTOR (NO. 4 RELAY BLOCK - BATTERY ECU ASSEMBLY)

CAUTION:

Be sure to wear insulated gloves and protective goggles.

(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) Remove the No. 1 HV battery hose.

Click here

(c) Disconnect the y16 battery ECU assembly connector.

NOTICE:

Before disconnecting the connector, check that it is not loose or disconnected.

(d) Remove the IGCT NO. 2 fuse from the No. 4 relay block.

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

*1

No. 4 Relay Block

*2

IGCT NO. 2 Fuse Holder

*a

Front view of wire harness connector

(to Battery ECU Assembly)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

y16-13 (IGCT) - 2 (IGCT NO. 2 fuse holder)

Always

Below 1 Ω

(f) Install the IGCT NO. 2 fuse.

(g) Reconnect the y16 battery ECU assembly connector.

(h) Install the No. 1 HV battery hose.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

CHECK HARNESS AND CONNECTOR (NO. 3 RELAY BLOCK - NO. 4 RELAY BLOCK)

(a) Remove the IGCT NO. 2 fuse from the No. 4 relay block.

(b) Remove the IGCT relay from the No. 3 relay block.

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

*1

No. 4 Relay Block

*2

No. 3 Relay Block

*3

IGCT NO. 2 Fuse Holder

*4

IGCT Relay Holder

Standard Resistance:

Tester Connection

Condition

Specified Condition

5 (IGCT relay holder 5) - 1 (IGCT NO. 2 fuse holder 1)

Always

Below 1 Ω

(d) Install the IGCT relay.

(e) Install the IGCT NO. 2 fuse.

OK

CHECK ECU Power Source Circuit (HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY))

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.

CHECK HARNESS AND CONNECTOR (NO. 4 RELAY BLOCK - BATTERY ECU ASSEMBLY)

CAUTION:

Be sure to wear insulated gloves and protective goggles.

(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) Remove the No. 1 HV battery hose.

Click here

(c) Disconnect the y16 battery ECU assembly connector.

NOTICE:

Before disconnecting the connector, check that it is not loose or disconnected.

(d) Remove the IGCT NO. 2 fuse from the No. 4 relay block.

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

*1

No. 4 Relay Block

*2

IGCT NO. 2 Fuse Holder

*a

Front view of wire harness connector

(to Battery ECU Assembly)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

y16-13 (IGCT) or 2 (IGCT-NO. 2 fuse holder) - Body ground and other terminals

Always

10 kΩ or higher

(f) Install the IGCT NO. 2 fuse.

(g) Reconnect the y16 battery ECU assembly connector.

(h) Install the No. 1 HV battery hose.

OK

REPLACE FUSE (IGCT NO. 2)
NG

7.

REPAIR OR REPLACE HARNESS OR CONNECTOR
NEXT

REPLACE FUSE (IGCT NO. 2)

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