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Home >> Toyota >> 2020 >> Highlander L, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 39 (Automatic Transmission System (UA81E / UA81F) - Diagnostic Codes (1 Of 3)) >> Automatic Transaxle System >> DTC P0615-12: Starter Relay Circuit Short to Battery [11/2023 - ] >> Procedure

DTC P0615-12: Starter Relay Circuit Short to Battery [11/2023 - ]: Procedure

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  1. READ VALUE USING GTS (STARTER SW) 
    1. Enter the following menus: Powertrain / Transmission / Data List / Starter SW.

      Powertrain > Transmission > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Starter SW Starter signal OFF or ON
      • ON: Starter operating
      • OFF: Starter not operating
      		 -

      Powertrain > Transmission > Data List 

      Tester Display
      Starter SW
    2. Read the Data List according to the display on the GTS.

      OK

      Condition Starter SW
      Ignition switch ON OFF
    3. Read the Data List according to the display on the GTS while the vehicle is being driven with an engine speed of 1000 rpm or more at a vehicle speed of 20 km/h (12 mph) or more.

      OK

      Condition Starter SW
      Driving at 20 km/h (12 mph) or more (engine speed 1000 rpm or more) OFF

      HINT: 

      If the result of either of the above is not as specified, proceed to the next step with the ignition switch ON, the GTS connected and Data List item "Starter SW" selected.

      Result

      Proceed to
      OK
      NG

      HINT: 

      If the starter assembly operates continuously when the ignition switch is turned to ON, proceed to the next step without reading the Data List item "Starter SW".

    Result: 

    OK 

    SYMPTOMS SIMULATION AND DTC CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

    Result: 

    NG 

    See step  2

  2. INSPECT ST RELAY (CHECK FOR SHORT CIRCUIT) 
    1. Enter the following menus: Powertrain / Transmission / Data List / Starter SW.

      Powertrain > Transmission > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Starter SW Starter signal OFF or ON
      • ON: Starter operating
      • OFF: Starter not operating
      		 -

      Powertrain > Transmission > Data List 

      Tester Display
      Starter SW
    2. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Read the Data List according to the display on the GTS.

      Result

      Result Proceed to
      The Data List item "Starter SW" does not change from ON. A
      The Data List item "Starter SW" changes from ON to OFF. B

      HINT: 

      • When the result of the above inspection is "The Data List item "Starter SW" does not change from ON", the ST relay is normal.
      • DTCs may be stored during this inspection. Check for DTCs and clear them using the GTS.

    Result: 

    B 

    REPLACE ST RELAY 

    Result: 

    A 

    See step  3

  3. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ST RELAY) 

    HINT: 

    The purpose of this step is to check for ST relay terminal voltage under abnormal conditions.

    1. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
      GTY1180483Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 ST Relay Holder
    2. Turn the ignition switch to ON.
    3. Measure the voltage between ST relay terminal 2 and body ground.

      HINT: 

      • Make a note of the measured voltage as it will be necessary for the inspecting the change in voltage in the next step. As the next step should be conducted under the same conditions, keep the ignition switch ON and do not install the ST relay.
      • DTCs may be stored during this inspection. Check for DTCs and clear them using the GTS.
      • If any voltage was measured with the ignition switch ON, one of the following malfunctions is suspected:
        • Short to +B in the circuit of a connected ECU or park/neutral position switch assembly.
        • Short to +B in the wire harness.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  4

  4. INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY (CHECK FOR SHORT CIRCUIT) 
    1. Disconnect the C52 park/neutral position switch assembly connector.
      GTY1180483Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 ST Relay Holder
    2. Measure the voltage between ST relay terminal 2 and body ground and compare it to the voltage measured in the previous step.

      Result

      Result Proceed to
      The voltage between ST relay terminal 2 and body ground does not change when the connector is disconnected (w/o Stop and Start System). A
      The voltage between ST relay terminal 2 and body ground does not change when the connector is disconnected (w/ Stop and Start System). B
      The voltage between ST relay terminal 2 and body ground changes when the connector is disconnected. C

      HINT: 

      • If the voltage is the same before and after disconnecting the connector, the park/neutral position switch assembly is normal.
      • DTCs may be stored during this inspection. Check for DTCs and clear them using the GTS.

    Result: 

    B 

    See step  8

    Result: 

    C 

    REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    A 

    See step  5

  5. INSPECT ECM (CHECK FOR SHORT CIRCUIT) 
    1. Disconnect the A83 ECM connector.
      GTY1180483Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 ST Relay Holder
    2. Measure the voltage between ST relay terminal 2 and body ground and compare it to the voltage measured in the previous step.

      Result

      Result Proceed to
      The voltage between ST relay terminal 2 and body ground does not change when the connector is disconnected. A
      The voltage between ST relay terminal 2 and body ground changes when the connector is disconnected. B

      HINT: 

      • If the voltage is the same before and after disconnecting the connector, the ECM is normal.
      • DTCs may be stored during this inspection. Check for DTCs and clear them using the GTS.

    Result: 

    B 

    See step  7

    Result: 

    A 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (ECM - PARK/NEUTRAL POSITION SWITCH ASSEMBLY - SMART KEY ECU ASSEMBLY - ST RELAY) 
    1. Disconnect the A83 ECM connector.
    2. Disconnect the C52 park/neutral position switch assembly connector.
    3. Disconnect the A88 certification ECU (smart key ECU assembly) connector.
    4. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A83-16 (STA), C52-9 (L), A88-3 (STA) or 2 (ST relay) - Other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK SMART KEY SYSTEM (CHECK FOR STA TERMINAL VOLTAGE OF SMART KEY ECU ASSEMBLY). Refer to  TERMINALS OF ECU [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  7. REPLACE ECM 

    Refer to REMOVAL [11/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    PERFORM REGISTRATION. Refer to  REGISTRATION [10/2022 - ] 

  8. INSPECT ECM (CHECK FOR SHORT CIRCUIT) 
    1. Disconnect the A83 ECM connector.
      GTY1180483Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 ST Relay Holder
    2. Measure the voltage between ST relay terminal 2 and body ground and compare it to the voltage measured in the previous step.

      Result

      Result Proceed to
      The voltage between ST relay terminal 2 and body ground does not change when the connector is disconnected. A
      The voltage between ST relay terminal 2 and body ground changes when the connector is disconnected. B

      HINT: 

      • If the voltage is the same before and after disconnecting the connector, the ECM is normal.
      • DTCs may be stored during this inspection. Check for DTCs and clear them using the GTS.

    Result: 

    B 

    See step  11

    Result: 

    A 

    See step  9

  9. INSPECT ENGINE STOP AND START ECU (CHECK FOR SHORT CIRCUIT) 
    1. Disconnect the A34 engine stop and start ECU connector.
      GTY1180483Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 ST Relay Holder
    2. Measure the voltage between ST relay terminal 2 and body ground and compare it to the voltage measured in the previous step.

      Result

      Result Proceed to
      The voltage between ST relay terminal 2 and body ground does not change when the connector is disconnected. A
      The voltage between ST relay terminal 2 and body ground changes when the connector is disconnected. B

      HINT: 

      • If the voltage is the same before and after disconnecting the connector, the engine stop and start ECU is normal.
      • DTCs may be stored during this inspection. Check for DTCs and clear them using the GTS.

    Result: 

    B 

    REPLACE ENGINE STOP AND START ECU. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    A 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (ECM - PARK/NEUTRAL POSITION SWITCH ASSEMBLY - SMART KEY ECU ASSEMBLY - ENGINE STOP AND START ECU - ST RELAY) 
    1. Disconnect the A83 ECM connector.
    2. Disconnect the C52 park/neutral position switch assembly connector.
    3. Disconnect the A88 certification ECU (smart key ECU assembly) connector.
    4. Disconnect the A34 engine stop and start ECU connector.
    5. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A83-16 (STA), C52-9 (L), A88-3 (STA), A34-21 (STA) or 2 (ST relay) - Other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK SMART KEY SYSTEM (CHECK FOR STA TERMINAL VOLTAGE OF SMART KEY ECU ASSEMBLY). Refer to  TERMINALS OF ECU [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - PARK/NEUTRAL POSITION SWITCH ASSEMBLY - SMART KEY ECU ASSEMBLY - ENGINE STOP AND START ECU - ST RELAY) 

  11. REPLACE ECM 

    Refer to REMOVAL [11/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    PERFORM REGISTRATION. Refer to  REGISTRATION [10/2022 - ] 

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