Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: DC/DC Converter Enable Component Internal Failure (P1CCC96)

DESCRIPTION

The DC/DC converter converts the DC 244.8 V of the HV battery into DC 12 V in order to supply power to areas such as the vehicle lighting system, audio system and various ECUs. Additionally, it charges the auxiliary battery.

A transistor bridge circuit initially converts DC 244.8 V into alternating current, and a transformer lowers the voltage.

The DC/DC converter controls the output voltage in order to keep a constant voltage at the terminals of the auxiliary battery.

Then, it is rectified and smoothed (into direct current) and converted into DC 12 V.

The motor generator control ECU sends a signal to the DC/DC converter to prohibit its control and receives signals indicating a normal or abnormal condition of the 12 V charging system via the NODD signal line.

If the DC/DC converter malfunctions, the vehicle will become inoperative. Therefore, the motor generator control ECU monitors the operation of the DC/DC converter and detects malfunctions.

This DTC is stored when the DC/DC converter circuit has a malfunction or its operation is prohibited by a fail-safe function, or the auxiliary battery voltage drops to 11 V or less with the power switch on (READY).

If a DC/DC converter malfunction occurs, DC/DC converter malfunction signals are sent from the DC/DC converter to the MG ECU via the NODD signal line.

This DTC may also be stored if a malfunction of the inverter cooling system (blockage, inverter water pump malfunction, etc.) or a high-voltage insulation malfunction occurs.

HINT:

*: If the DC/DC converter is malfunctioning, its operation and charging will be stopped and the auxiliary battery voltage will drop.

WIRING DIAGRAM

Refer to the wiring diagram for the Generator High-voltage Circuit.

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Refer to the wiring diagram for the Motor High-voltage Circuit.

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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.

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  HINT:

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

  

  *a	Without waiting for 10 minutes

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.

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HINT:

• After repair, clear the DTCs, turn the power switch off and wait for 30 seconds or more and perform the following procedure to confirm that the auxiliary battery low voltage indicated by this DTC has been repaired.
  1. Wait for 2 minutes with the shift lever in P, the power switch on (READY) and the following conditions met, then confirm that Data List item "BATT Voltage (Hybrid control system)" is between 13.0 and 15.0 V.

     (If charging is not performed and the electrical load increases, +B voltage may not be steady and will gradually drop.)

     1. Headlight switch is in the HI position.
     2. A/C blower fan switch is in the HI position.
     3. Window defogger switch is turned on.
• By performing the following procedure, the DC/DC converter function can be checked.
  1. Connect the AC/DC 400 A probe to the positive (+) auxiliary battery cable.
     1. Turn the power switch on (READY) and leave the vehicle as is until the electric current flowing to the auxiliary battery becomes 10 A or less.
     2. Turn the power switch on (READY) and turn the headlight switch and A/C blower fan switch to the HI position and the window defogger on.
     3. Confirm that the current drawn from the auxiliary battery is 0 A or lower and the auxiliary battery voltage is between 12.5 and 15.0 V.

• This DTC may be also stored when a part other than the DC/DC converter is malfunctioning or depending on user operation.

• If this vehicle is used to jump start another vehicle with a discharged battery, a fuse may blow due to overcurrent or the DC/DC converter self-protection may be activated. Also, if this vehicle is jump started by a vehicle with a 24 V battery, the same malfunction may occur and this DTC may be stored. (The suspended DC/DC converter control will return to normal by clearing the DTCs and turning the power switch off.)

• Confirm that high electrical load equipment such as a high-capacitance audio device or electric kettle is used in the vehicle. (A fuse of the auxiliary battery may be blown due to overcurrent.)

• If the DC/DC converter is malfunctioning, the auxiliary battery cannot be charged. Therefore, once the power switch is turned off, it may be impossible to turn it on (READY) again if the auxiliary battery is completely discharged. In this case, charge the auxiliary battery. Be careful as charging is not performed during the inspection.

• If the power switch turns off immediately after it is turned on (READY), the auxiliary battery voltage may be low. Charge the auxiliary battery.

PROCEDURE

(a) Connect the Techstream to the DLC3.

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

(c) Enter the following menus: Powertrain / Engine, Hybrid Control and Motor Generator / Trouble Codes.

(d) Check for DTCs.

HINT:

P1CCC96 may be output as a result of the malfunction indicated by the DTCs above.

1. The chart above is listed in inspection order of priority.
2. Check DTCs that are output at the same time by following the listed order. (The main cause of the malfunction can be determined without performing unnecessary inspections.)

(e) Turn the power switch off.

B

GO TO DTC CHART (HYBRID CONTROL SYSTEM)

C

GO TO DTC CHART (MOTOR GENERATOR CONTROL SYSTEM)

D

GO TO DTC CHART (SFI SYSTEM)

A

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 terminal are tightened to the specified torque, the AMD terminal is connected securely, and there are no contact problems. Torque: Inverter with converter assembly side T=10 N*m (102 kgf*cm, 7 ft.*lbf) No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly Side T=8.0 N*m (82 kgf*cm, 71 in.*lbf) Result Proceed to There are no arc marks. The terminal is connected securely and there are no contact problems. A There are no arc marks. The terminal is not connected securely and there is a contact problem. B There are arc marks. - C

*1 AMD Terminal (Inverter with Converter Assembly Side) *2 AMD Terminal (No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly Side)

B

CONNECT SECURELY

C

REPLACE MALFUNCTIONING PARTS

A

CAUTION:

Be sure to wear insulated gloves.

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

(b) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Condition Specified Condition 1G-1 (AMD) - Body ground Power switch off Same as auxiliary battery voltage

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

NG

REPLACE FUSIBLE LINK BLOCK ASSEMBLY (DC/DC)

OK

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 engine wire from the AMD terminal (inverter with converter assembly side and engine room R/B No. 1 side).

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

Standard Resistance:

(d) Install the engine wire.

NG

GO TO STEP 7

OK

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HINT:

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

(a) Connect the AC/DC 400 A probe of the tester to the positive (+) auxiliary battery cable.

(b) Install the service plug grip.

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

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

HINT:

If the power switch turns off immediately after it is turned on (READY), auxiliary battery voltage may be low. Recharge the auxiliary battery and perform this procedure again.

(e) 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:

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

Standard Voltage:

(g) Turn the power switch off.

OK

REPLACE INVERTER WITH CONVERTER ASSEMBLY

NG

GO TO STEP 8

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

(b) Remove the fusible link block assembly (DC/DC).

*1 Fusible link block assembly

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

Standard Resistance:

OK

REPAIR OR REPLACE WIRE HARNESS

NG

REPLACE FUSIBLE LINK BLOCK ASSEMBLY (DC/DC)

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 cover from the inverter with converter assembly.

(c) Using a megohmmeter set to 500 V, measure the insulation resistance according to the value(s) in the table below. 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: Tester Connection Condition Specified Condition W2-1 (W) - Body ground and shield ground Power switch off 1 MΩ or higher W2-2 (U) - Body ground and shield ground Power switch off 1 MΩ or higher W2-3 (V) - Body ground and shield ground Power switch off 1 MΩ or higher W2-4 (W) - Body ground and shield ground Power switch off 1 MΩ or higher W2-5 (U) - Body ground and shield ground Power switch off 1 MΩ or higher W2-6 (V) - Body ground and shield ground Power switch off 1 MΩ or higher HINT: Perform this inspection while the motor cable are connected.

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

OK

REPLACE INVERTER WITH CONVERTER ASSEMBLY

NG

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NEXT

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HINT:

If the "Motor High-voltage Circuit" inspection results are normal, perform the next step.

NEXT

REPLACE INVERTER WITH CONVERTER ASSEMBLY