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ECM Power and Ground Circuit Check: Troubleshooting

CAUTION: The connectors of the ECM are watertight. If tester probes are directly connected to any of the connectors when checking the ECM and its circuits, the watertight performance of the connector will be affected, possibly resulting in corrosion of connector terminals and damage to electrical circuits. Always use the special tool when checking the ECM and its circuits. Connect tester probes only to the special tool's connectors.
NOTE:

    Before troubleshooting, perform following items.

  • Be sure to read PRECAUTIONS FOR ECM CIRCUIT INSPECTION   .
  • Be sure to confirm related fuses of ECM power circuit for not blown out.

    If fuse is blown out, replace fuse(s) and check circuits connected to blown fuse(s) for short circuit to ground.

  • Confirm that battery voltage is 11 V or more.
  1. Check ECM power supply circuit as follows.
    1. Turn OFF ignition switch and disconnect ECM connectors from ECM.
    2. Check each terminal of ECM connectors for proper connection.
    3. Measure voltage between each terminal of ECM connector and body ground in the following table.

      If each measured voltage is out of specified voltage, repair or replace related part.

      VOLTAGE REFERENCE CHART

      Terminals Specified voltage Related part
      Ignition switch: OFF Ignition switch: ON
      "E01-2" to body ground Battery voltage Battery voltage Backup power supply circuit (A1)
      "E01-29" to body ground 0 -1 V
      • Ignition switch signal circuit (B1)
      • Ignition switch
      • ID controller (Canada model)
      "E01-60" to body ground Battery voltage
      • Main relay power supply circuit (C1)
      • Main relay drive circuit (C2)
      • Main relay (coil side)
    4. Turn OFF ignition switch and connect ECM connectors.
    5. Measure voltage between each terminal of ECM connector and body ground in the following table.

      If each measured voltage is out of specified voltage, repair or replace related part.

      VOLTAGE REFERENCE CHART

      Terminals Specified voltage Related part
      Ignition switch: After 3 sec. from ignition switch OFF Ignition switch: ON
      "E01-60" to body ground Battery voltage 0 - 1 V ECM
      "E01-1" to body ground 0 - 1 V Battery voltage
      • Main relay power supply circuit (switch side) (C3)
      • Main power supply circuit 1 (C4)
      • Main relay (switch side)
      "E01-16" to body ground 0 - 1 V Battery voltage
      • Main relay power supply circuit (switch side) (C3)
      • Main power supply circuit 2 (C5)
      • Main relay (switch side)
  2. Check throttle actuator power supply circuit as follows.
    VOLTAGE REFERENCE CHART

    Terminals Specified voltage Related part
    Ignition switch: OFF Ignition switch: ON
    "E01-49" to body ground 0 - 1 V
    • Throttle actuator control relay drive circuit (K2)
    • ECM
    "E01-31" to body ground 0 - 1 V Battery voltage
    • Throttle actuator control relay power supply circuit (coil side) (K1)
    • Throttle actuator control relay drive circuit (K2)
    • Throttle actuator control relay power supply circuit (switch side) (K3)
    • Throttle actuator power supply circuit (K4)
    • Throttle actuator control relay
    • ECM
  3. Check ECM ground circuit as follows.

    If each measured voltage is within specified voltage, go to next step.

    If each measured voltage is out of specified voltage, repair ECM ground circuits.

    VOLTAGE REFERENCE CHART

    Terminals Specified voltage Related part
    Ignition switch: OFF Ignition switch: ON
    "E01-2" to "C01-15" Battery voltage Battery voltage ECM ground circuit 1 (H1)
    "E01-2" to "C01-29" ECM ground circuit 3 (H3)
    "E01-2" to "C01-30" ECM ground circuit 2 (H2)
    "E01-2" to "C01-58" ECM ground circuit 4 (H4)
  4. Check each sensor power supply circuit as follows.

    If measured voltage is within specified voltage, ECM power and ground circuits is in good condition.

    If each measured voltage is out of specified voltage, repair or replace related part.

    VOLTAGE REFERENCE CHART

    Terminals Specified voltage Related part
    Ignition switch: OFF Ignition switch: ON
    "E01-56" to body ground 0 - 1 V 4 - 6 V
    • APP sensor (main) power supply circuit (E1)
    • APP sensor
    • ECM
    "E01-55" to body ground
    • APP sensor (sub) power supply circuit (E2)
    • APP sensor
    • ECM
    "E01-57" to body ground
    • A/C refrigerant pressure sensor power supply circuit (D1)
    • A/C refrigerant pressure sensor
    • ECM
    "C01-41" to body ground
    • TP sensor power supply circuit (F1)
    • TP sensor
    • ECM
    "E01-40" to body ground
    • EVAP leak check pressure sensor power supply circuit (L1)
    • EVAP leak check module
    • ECM
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