RX400h · Service Manual HYBRID SYSTEM

P0A05-776

Diagnostic trouble codes

DESCRIPTION

Refer to the circuit description of DTC P0A02-719 (Click here)
DTC No.
 INFO Code
 DTC Detection Condition
 Trouble Area
P0A05
 776
 Water pump malfunction
  1. Wire harness or connector
  2. Water pump w/ motor & bracket assembly
  3. HV control ECU

WIRING DIAGRAM

A113948E02

INSPECTION PROCEDURE


1. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (WATER PUMP)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to the ON position.

  1. Select the following menu items: Powertrain / Hybrid Control / Active Test / Active Water Pump.

  1. During the water pump active test, check operation of the water pump.

    OK:
    There are ripples in the reservoir tank coolant.

    HINT:
    The water pump is also activated in the READY-on state.



 NG
Go to step 5
OK


2. INSPECT HYBRID VEHICLE CONTROL ECU

  1. A111760E02
    Connect the intelligent tester to the DLC3.

  1. Put the vehicle into the READY-on state.

  1. Select the following menu items: Powertrain / Hybrid Control / Active Test / Active Water Pump.

  1. During the water pump active test, check for pulse signals according to the table below.

    Item
    		 Contents
    Terminal
    		 NIWP (H29-29) - E1 (H32-5)
    Equipment Setting
    		 5 V/DIV, 2 ms/DIV
    Condition
    		 During WATER PUMP active test

    OK:
    The waveform appears as shown in the illustration.



 OK
REPLACE HYBRID VEHICLE CONTROL ECU
NG


3. CHECK HARNESS AND CONNECTOR (HV CONTROL ECU - WATER PUMP)

  1. A105206E01
    Turn the ignition switch off.

  1. Disconnect the H29 connector from the HV control ECU.

  1. Disconnect the W5 water pump connector.

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

    Standard Resistance (Check for open):
    Tester Connection
    		 Specified Condition
    IWP (H29-23) - SWP (W5-2)
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4. INSPECT WATER PUMP W/ MOTOR & BRACKET ASSEMBLY

  1. A111744E01
    Disconnect the W5 water pump connector.

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    NWP (W5-1) - GND (W5-3)
    		 1 MΩ or higher



NG
REPLACE WATER PUMP W/ MOTOR & BRACKET ASSEMBLY
OK

REPLACE HYBRID VEHICLE CONTROL ECU

5. CHECK HARNESS AND CONNECTOR (WATER PUMP)

  1. Turn the ignition switch off.

  1. A108018E01
    Disconnect the W5 water pump w/ motor & bracket assembly connector.

  1. A114855E01
    Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		 Specified Condition
    +BWP (W5-4) - GND (W5-3)
    		 10 to 14 V



NG
INSPECT POWER SOURCE CIRCUIT OF WATER PUMP W/ MOTOR & BRACKET ASSEMBLY
OK


6. CHECK COOLANT HOSE

  1. A105138E02
    Check if the hoses of the cooling system are not bent or clogged.

    OK:
    The hoses of the cooling system are not bent or clogged.



 NG
CORRECT TO NORMAL CONDITION
OK


7. CHECK HARNESS AND CONNECTOR (HV CONTROL ECU - WATER PUMP)

  1. A105206E01
    Turn the ignition switch off.

  1. Disconnect the H29 connector from the HV control ECU.

  1. Disconnect the W5 water pump w/ motor & bracket assembly connector.

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

    Standard Resistance:
    Tester Connection
    		 Specified Condition
    IWP (H29-23) - SWP (W5-2)
    		 Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


8. INSPECT HYBRID VEHICLE CONTROL ECU

  1. A103658E39
    Connect the HV control ECU connector and water pump w/ motor & bracket assembly connector.

  1. Turn the ignition switch to the ON position.

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

    Standard Voltage:
    Tester Connection
    		 Specified Condition
    IWP (H29-23) - E1 (H32-5)
    		 Below 1 V



OK
Go to step 10
NG


9. INSPECT WATER PUMP W/ MOTOR & BRACKET ASSEMBLY (SWP TERMINAL VOLTAGE)

  1. A103664E04
    Disconnect the H29 connector from the HV control ECU.

  1. Turn the ignition switch to the ON position.

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

    Standard Voltage:
    Tester Connection
    		 Specified Condition
    IWP (H29-23) - E1 (H32-5)
    		 10 to 14 V



NG
REPLACE WATER PUMP W/ MOTOR & BRACKET ASSEMBLY
OK

REPLACE HYBRID VEHICLE CONTROL ECU

10. INSPECT HYBRID VEHICLE CONTROL ECU

  1. A103658E39
    Put the vehicle into the READY-on state.

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

    Standard Voltage:
    Tester Connection
    		 Specified Condition
    IWP (H29-23) - E1 (H32-5)
    		 10 to 14 V



OK
REPLACE WATER PUMP W/ MOTOR & BRACKET ASSEMBLY
NG

REPLACE HYBRID VEHICLE CONTROL ECU


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