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Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 123 (Automatic Transaxle System - Diagnostic Codes (1 Of 3)) >> Automatic Transaxle System >> DTC P0615-12: Starter Relay Circuit Short to Battery [10/2022 - ] >> Procedure

DTC P0615-12: Starter Relay Circuit Short to Battery [10/2022 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
  1. READ VALUE USING GTS (STARTER SW) 
    1. According to the display on the GTS, read the Data List.

      Powertrain > Transmission > Data List 

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

      Powertrain > Transmission > Data List 

      Tester Display
      Starter SW

      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.
      • 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

      Result Proceed to
      The value of Starter SW is OFF A
      None of the above conditions are met B

    Result: 

    See step  3

    Result: 

    See step  2

  2. READ VALUE USING GTS (STARTER SW) 
    1. 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.

      Powertrain > Transmission > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Vehicle Speed Vehicle speed Min.: 0 km/h (0 mph)
      Max.: 255 km/h (158 mph)
      Actual vehicle speed
      • This is the current vehicle speed.
      • The vehicle speed is detected using the wheel speed sensors.
        • Vehicle speed data is delayed when it is displayed. Therefore, even if the vehicle speed listed in the freeze frame data is 0 km/h (0 mph), this does not always mean that the malfunction occurred when the vehicle was stopped.
      Engine Speed Engine Speed Min.: 0 rpm
      Max.: 16383 rpm
      650 to 750 rpm: Engine idling (park (P) selected, engine warmed up and A/C off) When the crankshaft position sensor is malfunctioning, "Engine Speed" is approximately 0 rpm or varies greatly from the actual engine speed.
      Starter SW Starter signal ON or OFF
      • ON: Starter operating
      • OFF: Starter not operating
      -

      Powertrain > Transmission > Data List 

      Tester Display
      Vehicle Speed
      Engine Speed
      Starter SW

      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.

      Standard

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

      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

      Proceed to
      OK
      NG

    Result: 

    OK 

    SYMPTOMS SIMULATION AND DTC CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ] 

    Result: 

    NG 

    See step  3

  3. INSPECT ST NO. 1RELAY (CHECK FOR SHORT CIRCUIT) 

    Pre-procedure1

    • 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
    • Remove the ST NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    • Read the Data List according to the display on the GTS.

      HINT: 

      • When the result of the above inspection is "The Data List item "Starter SW" does not change from ON", the ST NO. 1 relay is normal.
      • DTCs may be stored during this inspection. Check for DTCs and clear them using 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

    Post-procedure1

    • None

    Result: 

    REPLACE ST NO. 1 RELAY 

    Result: 

    See step  4

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

    HINT: 

    The purpose of this step is to check for ST NO. 1 relay terminal voltage under abnormal conditions.

    Pre-procedure1

    • Remove the ST NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    • Turn the ignition switch to ON.
    • Measure the voltage between ST NO. 1 relay terminal 2 and body ground.
      GTY1127102Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 ST NO. 1 Relay Holder

      HINT: 

      • Make a note of the measured voltage as it will be necessary for 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 NO. 1 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.
        • Short to +B in the wire harness.

      Result

      Proceed to
      NEXT

    Post-procedure1

    • None

    Result: 

    NEXT 

    See step  5

  5. INSPECT ENGINE STOP AND START ECU (CHECK FOR SHORT CIRCUIT) 

    Pre-procedure1

    • Disconnect the A25 engine stop and start ECU connector.
    • Measure the voltage between ST NO. 1 relay terminal 2 and body ground and compare it to the voltage measured in the previous step.
      GTY1127102Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 ST NO. 1 Relay Holder

      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

      Result Proceed to
      The voltage between ST NO. 1 relay terminal 2 and body ground does not change when the connector is disconnected. A
      The voltage between ST NO. 1 relay terminal 2 and body ground changes when the connector is disconnected. B

    Post-procedure1

    • None

    Result: 

    REPLACE ENGINE STOP AND START ECU. Refer to  REMOVAL [10/2022 - ] 

    Result: 

    See step  6

  6. INSPECT ECM (CHECK FOR SHORT CIRCUIT) 

    Pre-procedure1

    • Disconnect the A16 ECM connector.
    • Measure the voltage between ST NO. 1 relay terminal 2 and body ground and compare it to the voltage measured in the previous step.
      GTY1127102Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 ST NO. 1 Relay Holder

      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

      Result Proceed to
      The voltage between ST NO. 1 relay terminal 2 and body ground does not change when the connector is disconnected. A
      The voltage between ST NO. 1 relay terminal 2 and body ground changes when the connector is disconnected. B

    Post-procedure1

    • None

    Result: 

    See step  8

    Result: 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (ECM - ENGINE STOP AND START ECU - SMART KEY ECU ASSEMBLY - ST RELAY) 

    Pre-procedure1

    • Disconnect the A16 ECM connector.
    • Disconnect the A7 certification ECU (smart key ECU assembly) connector.
    • Disconnect the A25 engine stop and start ECU connector.
    • Remove the ST NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      A16-16 (STA), A25-21 (STA), A7-10 (STAR), A7-3 (STA) or 2 (ST NO. 1 relay) - Other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    OK 

    CHECK SMART ACCESS SYSTEM WITH PUSH-BUTTON START (CHECK FOR STA TERMINAL VOLTAGE OF SMART KEY ECU ASSEMBLY). Refer to  TERMINALS OF ECU [10/2022 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  8. REPLACE ECM 

    HINT: 

    Refer to REMOVAL [10/2022 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

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