STOP AND START SYSTEM(for 1AD-FTV), Diagnostic DTC:P2531

DTC Code DTC Name
P2531 Ignition Switch Run Position Circuit Low

DESCRIPTION

When the engine stop and start ECU receives the OFF signal from the ignition or starter switch assembly*1 or certification ECU (smart key ECU assembly)*2 when communication with the ECM is normal, the engine stop and start ECU stores DTC P2531.

  • *1: w/o Entry and Start System

  • *2: w/ Entry and Start System

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Memory

P2531

Ignition Switch Run Position Circuit Low

Both of the following conditions continue for 10 seconds or more (1 trip detection logic):

  • Ignition switch OFF signal is input.

  • Communication with the ECM is normal.

  • Wire harness or connector

  • IG2 relay

  • EFI-MAIN NO. 2 relay

  • Ignition or starter switch assembly (w/o Entry and Start System)

  • Certification ECU (Smart key ECU assembly) (w/ Entry and Start System)

  • Engine stop and start ECU

Does not come on

DTC stored

CONFIRMATION DRIVING PATTERN

Tip:

DTCs for the stop and start system are not cleared even if the malfunction has been repaired. After repairing the malfunction, be sure to clear the DTCs.

Click here

  1. Tip:

    • When the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited for a certain amount of time. After connecting the cable, drive the vehicle until stop and start control is permitted (approximately 15 to 40 minutes).

    • Allow the engine to idle for 3 minutes after the engine warms up and check that the engine speed is within 50 rpm of the target idle speed.

    CONFIRMATION AFTER TROUBLESHOOTING

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.

      Click here

      Powertrain > Stop and Start > Clear DTCs

    4. Start the engine and warm it up.

    5. Drive the vehicle at 7 km/h (4.3 mph) or more.

      CAUTION:

      When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    6. Stop the vehicle, move the shift lever to neutral and release the clutch pedal.

    7. Keep the engine stopped by stop and start control for 1 second or more.

    8. Depress the clutch pedal and start the engine.

      Tip:

      If the engine cranks slowly when the engine is restarted, it can be determined that battery voltage is low.

    9. Check that DTCs are not output.

      Click here

      Powertrain > Stop and Start > Trouble Codes

  2. STOP AND START SYSTEM OPERATION CHECK

    Tip:

    When the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited for a certain amount of time. After connecting the cable, drive the vehicle until stop and start control is permitted (approximately 15 to 40 minutes).

    1. Start the engine and warm it up.

    2. Turn the air conditioning system off.

    3. Drive the vehicle at 7 km/h (4.3 mph) or more.

      CAUTION:

      When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    4. Stop the vehicle, move the shift lever to neutral and release the clutch pedal.

    5. Allow the engine to stop by stop and start control

    6. Depress the clutch pedal and start the engine.

WIRING DIAGRAM

A299563E01
A299564E01

CAUTION / NOTICE / HINT

Note:

  • Before replacing the engine stop and start ECU, read the number of starter operations and write it into a new engine stop and start ECU.

    Click here

  • After replacing the engine stop and start ECU or air conditioning amplifier assembly, reset and perform learning of the air conditioning information in the engine stop and start ECU.

    Click here

  • After replacing the engine stop and start ECU or airbag sensor assembly, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

Tip:

  • DTCs for the stop and start system are not cleared even if the malfunction has been repaired. After repairing the malfunction, be sure to clear the DTCs.

    Click here

  • Using the GTS, read the freeze frame data before troubleshooting. System condition information is recorded as freeze frame data the moment a DTC is stored. This information can be useful when troubleshooting.

    Click here

PROCEDURE

  1. READ VALUE USING GTS (IG SWITCH)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Stop and Start / Data List / IG Switch.

      Powertrain > Stop and Start > Data List

      Tester Display

      IG Switch

    5. Read the value displayed on the GTS.

      Result

      Tester Display

      Result

      Proceed to

      IG Switch

      OFF

      A

      ON

      B
    B

    USE SIMULATION METHOD TO CHECK

    Click hereClick hereClick hereClick here

    A

  2. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - IG2 RELAY)

    1. Disconnect the A61 ECM connector.

    2. Disconnect the G87 engine stop and start ECU connector.

    3. Remove the IG2 relay from engine room relay block and junction block assembly.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      G87-20 (IG2) - IG2 relay terminal 5

      Always

      Below 1 Ω

      G87-20 (IG2) - Body ground

      Always

      10 kΩ or higher

      IG2 relay terminal 5 - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT RELAY (IG2 RELAY)

    1. Inspect the IG2 relay.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE RELAY (IG2 RELAY)

    OK

  4. CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND)

    1. Remove the IG2 relay from engine room relay block and junction block assembly.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      IG2 relay terminal 2 - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (IG2 RELAY - IGNITION OR STARTER SWITCH ASSEMBLY OR CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))

    1. Remove the IG2 relay from engine room relay block and junction block assembly.

    2. w/o Entry and Start System:

      Disconnect the G4 ignition or starter switch assembly connector.

    3. w/ Entry and Start System:

      Disconnect the G82 certification ECU (smart key ECU assembly) connector.

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

      Standard Resistance

      Table 1. w/o Entry and Start System

      Tester Connection

      Condition

      Specified Condition

      IG2 relay terminal 1 - G4-3 (IG2)

      Always

      Below 1 Ω

      IG2 relay terminal 1 - Body ground

      Always

      10 kΩ or higher

      G4-3 (IG2) - Body ground

      Always

      10 kΩ or higher
      Table 2. w/ Entry and Start System

      Tester Connection

      Condition

      Specified Condition

      IG2 relay terminal 1 - G82-9 (IG2D)

      Always

      Below 1 Ω

      IG2 relay terminal 1 - Body ground

      Always

      10 kΩ or higher

      G82-9 (IG2D) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - EFI-MAIN NO. 2 RELAY)

    1. Disconnect the A65 engine stop and start ECU connector.

    2. Remove the EFI-MAIN NO. 2 relay from engine room relay block and junction block assembly.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A65-5 (+B) - EFI-MAIN NO. 2 relay terminal 3

      Always

      Below 1 Ω

      A65-5 (+B) - Body ground

      Always

      10 kΩ or higher

      EFI-MAIN NO. 2 relay terminal 3 - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK ECM (IGSW TERMINAL VOLTAGE)

    1. A194151C16

      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the A61 ECM connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      A61-25 (IGSW) - Body ground

      Ignition switch ON

      9.5 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    GO TO ECM POWER SOURCE CIRCUIT

    Click here

    OK

  8. INSPECT RELAY (EFI-MAIN NO. 2 RELAY)

    1. Inspect the EFI-MAIN NO. 2 relay.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE RELAY (EFI-MAIN NO. 2 RELAY)

    OK

  9. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - ECM)

    1. Remove the EFI-MAIN NO. 2 relay from engine room relay block and junction block assembly.

    2. Disconnect the A61 ECM connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      EFI-MAIN NO. 2 relay terminal 1 - A61-45 (MREL)

      Always

      Below 1 Ω

      EFI-MAIN NO. 2 relay terminal 1 - Body ground

      Always

      10 kΩ or higher

      A61-45 (MREL) - Body ground

      Always

      10 kΩ or higher

      Result

      Proceed to

      OK (w/o Entry and Start System)

      OK (w/ Entry and Start System)

      NG
    OK (w/ Entry and Start System)

    CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (IG2D TERMINAL VOLTAGE)Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK (w/o Entry and Start System)

  10. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY

    1. Inspect the ignition or starter switch assembly.

      Click here

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ENGINE STOP AND START ECU

    Click hereClick here

    NG

    REPLACE IGNITION OR STARTER SWITCH ASSEMBLY

    Click here

  11. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (IG2D TERMINAL VOLTAGE)

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

      B264896C40

      *a

      Component without harness connected

      (Certification ECU (Smart Key ECU Assembly))

      -

      -

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      G82-9 (IG2D) - Body ground

      Ignition switch ACC

      Below 1 V

      G82-9 (IG2D) - Body ground

      Ignition switch ON

      (+B)-2 V or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ENGINE STOP AND START ECU

    Click hereClick here

    NG

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)