Part 1

HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM: P0A08-264: DC / DC Converter Status Circuit
P0A08-264 - DC / DC Converter Status Circuit

DESCRIPTION

The hybrid vehicle converter (DC/DC converter) converts the DC 288 V of the HV battery into DC 12 V in order to supply power to areas such as the vehicle's lighting, audio, and ECU systems. In addition, it charges the auxiliary battery. A transistor bridge circuit initially converts DC 288 V into alternating current, and a transformer lowers its voltage. Then, it is rectified and smoothed (into DC) and converted into DC 12 V. The hybrid vehicle converter controls the output voltage in order to keep a constant voltage at the terminals of the auxiliary battery.

The power management control ECU (HV CPU) uses the NODD signal line to transmit a stop command to the hybrid vehicle converter and receive signals indicating the normal or abnormal condition of the 12 V charging system. If the vehicle is being driven with an inoperative hybrid vehicle converter, the voltage of the auxiliary battery will drop, which will prevent the continued operation of the vehicle. Therefore, the power management control ECU (HV CPU) monitors the operation of the hybrid vehicle converter and alerts the driver if it detects a malfunction.

WIRING DIAGRAM

INSPECTION PROCEDURE

CAUTION:
- Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with converter assembly, take safety precautions such as wearing insulated gloves and removing the service plug grip to prevent electrical shocks. After removing the service plug grip, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
- After disconnecting 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.
HINT
Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

PROCEDURE

1. CHECK DTC OUTPUT (HV)

(a) Connect the Techstream to the DLC3.

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

(c) Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

(d) Check if DTCs are output.

Result:

(e) Turn the power switch off.

B -- GO TO DTC CHART Hybrid Control System
A -- Continue to next step.

2. CHECK FUSE (IGCT NO. 2)

(a) Disconnect the cable from the negative auxiliary battery terminal.

(b) Remove the IGCT No. 2 fuse from the engine room relay block No. 2.

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

Standard Resistance:

Text in Illustration

(d) Install the IGCT No. 2 fuse.

NG -- CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - IGCT NO. 2 FUSE)
OK -- Continue to next step.

3. CHECK FUSE (DCDC-S)

(a) Remove the DCDC-S fuse from the fusible link block assembly.

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

Standard Resistance:

Text in Illustration

(c) Install the DCDC-S fuse.

NG -- CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - DCDC-S FUSE)
OK -- Continue to next step.

4. CHECK FUSIBLE LINK BLOCK ASSEMBLY (MAIN, RR-B)

(a) Disconnect all the connectors from the fusible link block assembly.

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

Standard Resistance:

Text in Illustration

(c) Connect the fusible link block assembly connectors.

NG -- REPLACE FUSIBLE LINK BLOCK ASSEMBLY (MAIN, RR-B)
OK -- Continue to next step.

5. CHECK FUSIBLE LINK BLOCK ASSEMBLY (DCDC, HV R/B NO. 1)

(a) Check the fusible links (DCDC and HV R/B NO.1) in the engine room junction block assembly for improper installation and for open circuits.

OK:

The fusible links are installed securely. There are no open circuits.

NG -- REPLACE FUSIBLE LINK BLOCK ASSEMBLY (DCDC, HV R/B NO.1)
OK -- Continue to next step.

6. CHECK CONNECTOR CONNECTION CONDITION (POWER MANAGEMENT CONTROL ECU CONNECTOR) P0340

NG -- CONNECT SECURELY
OK -- Continue to next step.

7. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR) P0343

NG -- CONNECT SECURELY
OK -- Continue to next step.

8. CHECK CABLE AND WIRE HARNESS

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) Remove the inverter terminal cover from the inverter with converter assembly.

NOTICE:
Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

Standard Resistance:

Text in Illustration

HINT
Perform this inspection while the three-phase AC cable for MG1 and for MG2 are connected.

(d) Install the inverter terminal cover to the inverter with converter assembly.

NG -- CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MG1)
OK -- Continue to next step.

9. CHECK AMD TERMINAL

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) Check that the nuts for the AMD terminals are tightened to the specified torque, the AMD terminals are connected securely, and there are no contact problems.

Torque : 8.35 Nm (85 kgf-cm)

Result:

C -- REPLACE MALFUNCTIONING PARTS

B -- CONNECT SECURELY
A -- Continue to next step.

10. CHECK TERMINAL VOLTAGE (AMD TERMINAL)

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) Connect the cable to the negative auxiliary battery terminal.

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

Standard Voltage:

NG -- CHECK AMD TERMINAL (ENGINE ROOM JUNCTION BLOCK ASSEMBLY SIDE)
OK -- Continue to next step.

11. CHECK HARNESS AND CONNECTOR

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 the A79 connector from the inverter with converter assembly.

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

HINT
Turning the power switch on (IG) with the service grip removed causes interlock switch system DTC P0A0D-350 to be output.

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

Standard Voltage:

Text in Illustration

(e) Turn the power switch off.

(f) Connect the inverter with converter assembly connector.

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

12. CHECK POWER MANAGEMENT CONTROL ECU

(a) Disconnect the A79 connector from the inverter with converter assembly.

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

Standard Resistance:

Text in Illustration

(c) Connect the inverter with converter assembly connector.

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

13. CHECK DC/DC CONVERTER FUNCTION

HINT
The current at the AMD terminal cannot be measured directly because of space limitations. Measure the current flowing from the auxiliary battery instead.

(a) Connect the AC/DC 400 A probe to the positive auxiliary battery line.

(b) Install the service plug grip.

(c) Turn the power switch on (READY) and leave the vehicle as it is until the electric current flowing into the auxiliary battery becomes 10 A or less.

(d) Measure the current flowing from the auxiliary battery with the power switch on (READY), the headlight position switch and blower motor switch in the HI position, and the rear window defogger turned on.

Standard Current:

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

Standard Voltage:

(f) Turn the power switch off.

NG -- REPLACE INVERTER WITH CONVERTER ASSEMBLY Components
OK -- Continue to next step.

14. CHECK QUANTITY OF HV COOLANT P0A01

C -- INSPECT FOR COOLANT LEAK AND ADD COOLANT

B -- ADD HV COOLANT
A -- Continue to next step.