Lexus ES: DC/DC Converter Enable Circuit Short to Battery (P0A1112,P0A1114)

DESCRIPTION

Refer to the description for DTC P1CCC96.

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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 (below 11 V) condition of the 12 V charging system from the DC/DC converter via the NODD signal line.

If the vehicle is being driven with an inoperative DC/DC converter, the voltage of the auxiliary battery will drop, which will prevent the continued operation of the vehicle. Therefore, the motor generator control ECU monitors the operation of the DC/DC converter and alerts the driver if it detects a malfunction.

CONFIRMATION DRIVING PATTERN

HINT:

After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

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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.

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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:

If the NODD signal line is open, DC/DC converter control will be prohibited and the auxiliary battery voltage will be approximately 12 V or less.

PROCEDURE

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B

CONNECT SECURELY

C

REPAIR OR REPLACE HARNESS OR CONNECTOR

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) Disconnect the A58 inverter with converter assembly connector.

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

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

Standard Resistance:

(e) Install the IGCT relay.

(f) Reconnect the A58 inverter with converter assembly connector.

OK

REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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