Inspection Procedure 26: Ignition circuit system










OPERATION



  • The battery voltage is applied to the ignition coil (terminal No. 3) from the ignition switch and is earthed to the vehicle body from the ignition coil (terminal No. 1).
  • A power voltage of 12 V is applied to the ignition coil output terminal (terminal No. 2) from the engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminals No. 31, No. 32, No. 35, No. 36, No. 44 and No. 52).

FUNCTION



  • When the engine-ECU <M/T> or engine-A/T-ECU <A/T> makes the power transistor in the unit be in OFF position, the battery voltage in the unit is applied to the power transistor unit, and that makes the power transistor unit be in ON position. The engine-ECU <M/T> or engine-A/T-ECU <A/T> makes the power transistor in the unit be in ON, and that makes the power transistor unit be in OFF position.
  • In response to the signal from the engine-ECU <M/T> or engine-A/T-ECU <A/T>, the power transistor unit is in ON position. The primary current is going to the ignition coil. When the power transistor unit is in OFF position, the primary current is interrupted and high voltage is generated in the secondary coil.

PROBABLE CAUSES



  • Failed ignition coil
  • Failed spark plug
  • Open/short circuit in ignition primary circuit or loose connector contact
  • Failed engine-ECU <M/T> or engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. Check spark plug.

  • Check spark plug itself (Refer to GROUP 16 - Ignition System <6G7> - On-vehicle Service - Spark Plug Check and Cleaning ).

Q. Is the check result normal?
Go to Step 2 .
Replace the spark plug.

STEP 2. Connector check: B-07, B-08, B-25, B-29, B-30 and B-33 ignition coil connectors

Q. Is the check result normal?

Go to Step 3 .
Repair or replace the connector.

STEP 3. Check ignition coil itself.

  • Check ignition coil itself (Refer to GROUP 16 - Ignition System <6G7> - On-vehicle Service - Ignition Coil Check ).

Q. Is the check result normal?

Go to Step 4 .
Replace the ignition coil.

STEP 4. Perform voltage measurement at B-07, B-08, B-25, B-29, B-30 and B-33 ignition coil connectors.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 3 and earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 6 .
Go to Step 5 .

STEP 5. Connector check: D-309 ignition switch connector

Q. Is the check result normal?


    Check intermediate connectors B-49, D-299, D-403 and D-405, and repair if necessary. If intermediate connectors are normal, check and repair harness between ignition switch connector and ignition coil connector

  1. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-29 (terminal No. 3) No. 1 ignition coil connector
  2. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-25 (terminal No. 3) No. 2 ignition coil connector
  3. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-30 (terminal No. 3) No. 3 ignition coil connector
  4. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-08 (terminal No. 3) No. 4 ignition coil connector
  5. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-33 (terminal No. 3) No. 5 ignition coil connector
  6. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-07 (terminal No. 3) No. 6 ignition coil connector

  • Check power supply line for open/short circuit.
Repair or replace the connector.

STEP 6. Perform voltage measurement at B-07, B-08, B-25, B-29, B-30 and B-33 ignition coil connectors.

  • Disconnect connector, and measure at harness side.
  • Engine: Cranking
  • Voltage between terminal No. 2 and earth.
OK: 0.3 - 3.0 V

Q. Is the check result normal?

Go to Step 12 .
Go to Step 7 .

STEP 7. Perform voltage measurement at D-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> connector.

  • Measure engine-ECU <M/T> or engine-A/T-ECU <A/T> terminal voltage.
  • Disconnect B-07, B-08, B-25, B-29, B-30 and B-33 ignition coil connectors.
  • Engine: Cranking

  1. Voltage between terminal No. 31 and earth (No. 1 Ignition coil).
  2. Voltage between terminal No. 35 and earth (No. 2 Ignition coil).
  3. Voltage between terminal No. 44 and earth (No. 3 Ignition coil).
  4. Voltage between terminal No. 52 and earth (No. 4 Ignition coil).
  5. Voltage between terminal No. 32 and earth (No. 5 Ignition coil).
  6. Voltage between terminal No. 36 and earth (No. 6 Ignition coil).
OK: 0.3 - 3.0 V

Q. Are the check results normal?

Go to Step 8 .
Go to Step 9 .

STEP 8. Connector check: D-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> connector

Q. Is the check result normal?


    Check intermediate connector B-49, and repair if necessary. If intermediate connector is normal, check and repair harness between ignition coil connector and engine-ECU <M/T> or engine-A/T-ECU <A/T> connector

  1. Check and repair harness between B-29 (terminal No. 2) No. 1 ignition coil connector and D-244 (terminal No. 31) engine-ECU <M/T> connector or D-214 (terminal No. 31) engine-A/T-ECU <A/T> connector.
  2. Check and repair harness between B-25 (terminal No. 2) No. 2 ignition coil connector and D-244 (terminal No. 35) engine-ECU <M/T> connector or D-214 (terminal No. 35) engine-A/T-ECU <A/T> connector.
  3. Check and repair harness between B-30 (terminal No. 2) No. 3 ignition coil connector and D-244 (terminal No. 44) engine-ECU <M/T> connector or D-214 (terminal No. 44) engine-A/T-ECU <A/T> connector.
  4. Check and repair harness between B-08 (terminal No. 2) No. 4 ignition coil connector and D-244 (terminal No. 52) engine-ECU <M/T> connector or D-214 (terminal No. 52) engine-A/T-ECU <A/T> connector.
  5. Check and repair harness between B-33 (terminal No. 2) No. 5 ignition coil connector and D-244 (terminal No. 32) engine-ECU <M/T> connector or D-214 (terminal No. 32) engine-A/T-ECU <A/T> connector.
  6. Check and repair harness between B-07 (terminal No. 2) No. 6 ignition coil connector and D-244 (terminal No. 36) engine-ECU <M/T> connector or D-214 (terminal No. 36) engine-A/T-ECU <A/T> connector

  • Check output line for open circuit.
Repair or replace the connector.

STEP 9. Connector check: D-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> connector

Q. Is the check result normal?

Go to Step 10 .
Repair or replace the connector.

STEP 10. Check harness between ignition coil connector and engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector.
note Before checking harness, check intermediate connector B-49, and repair if necessary.

  1. Check and repair harness between B-29 (terminal No. 2) No. 1 ignition coil connector and D-244 (terminal No. 31) engine-ECU <M/T> connector or D-214 (terminal No. 31) engine-A/T-ECU <A/T> connector.
  2. Check and repair harness between B-25 (terminal No. 2) No. 2 ignition coil connector and D-244 (terminal No. 35) engine-ECU <M/T> connector or D-214 (terminal No. 35) engine-A/T-ECU <A/T> connector.
  3. Check and repair harness between B-30 (terminal No. 2) No. 3 ignition coil connector and D-244 (terminal No. 44) engine-ECU <M/T> connector or D-214 (terminal No. 44) engine-A/T-ECU <A/T> connector.
  4. Check and repair harness between B-08 (terminal No. 2) No. 4 ignition coil connector and D-244 (terminal No. 52) engine-ECU <M/T> connector or D-214 (terminal No. 52) engine-A/T-ECU <A/T> connector.
  5. Check and repair harness between B-33 (terminal No. 2) No. 5 ignition coil connector and D-244 (terminal No. 32) engine-ECU <M/T> connector or D-214 (terminal No. 32) engine-A/T-ECU <A/T> connector.
  6. Check and repair harness between B-07 (terminal No. 2) No. 6 ignition coil connector and D-244 (terminal No. 36) engine-ECU <M/T> connector or D-214 (terminal No. 36) engine-A/T-ECU <A/T> connector.

  • Check output line for short circuit.

Q. Are the check results normal?

Go to Step 11 .
Repair the damaged harness wire.

STEP 11. Check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

STEP 12. Perform resistance measurement at B-07, B-08, B-25, B-29, B-30 and B-33 ignition coil connectors.

  • Disconnect connector, and measure at harness side.
  • Resistance between terminal No. 1 and earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 13.

    Check intermediate connector B-49, and repair if necessary. If intermediate connector is normal, check and repair harness between ignition coil connector and body earth

  1. Check and repair harness between B-29 (terminal No. 1) No. 1 ignition coil connector and body earth
  2. Check and repair harness between B-25 (terminal No. 1) No. 2 ignition coil connector and body earth
  3. Check and repair harness between B-30 (terminal No. 1) No. 3 ignition coil connector and body earth
  4. Check and repair harness between B-08 (terminal No. 1) No. 4 ignition coil connector and body earth
  5. Check and repair harness between B-33 (terminal No. 1) No. 5 ignition coil connector and body earth
  6. Check and repair harness between B-07 (terminal No. 1) No. 6 ignition coil connector and body earth

  • Check earthing line for open circuit and damage.

STEP 13. Check harness between ignition switch connector and ignition coil connector.
note Before checking harness, check intermediate connectors B-49, D-299, D-403 and D-405, and repair if necessary.

  1. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-29 (terminal No. 3) No. 1 ignition coil connector
  2. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-25 (terminal No. 3) No. 2 ignition coil connector
  3. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-30 (terminal No. 3) No. 3 ignition coil connector
  4. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-08 (terminal No. 3) No. 4 ignition coil connector
  5. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-33 (terminal No. 3) No. 5 ignition coil connector
  6. Check and repair harness between D-309 (terminal No. 2) ignition switch connector and B-07 (terminal No. 3) No. 6 ignition coil connector

  • Check power supply line for damage.

Q. Are the check results normal?

Go to Step 14 .
Repair the damaged harness wire.

STEP 14. Check harness between ignition coil connector and engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector.
note Before checking harness, check intermediate connector B-49, and repair if necessary.

  1. Check and repair harness between B-29 (terminal No. 2) No. 1 ignition coil connector and D-244 (terminal No. 31) engine-ECU <M/T> connector or D-214 (terminal No. 31) engine-A/T-ECU <A/T> connector.
  2. Check and repair harness between B-25 (terminal No. 2) No. 2 ignition coil connector and D-244 (terminal No. 35) engine-ECU <M/T> connector or D-214 (terminal No. 35) engine-A/T-ECU <A/T> connector.
  3. Check and repair harness between B-30 (terminal No. 2) No. 3 ignition coil connector and D-244 (terminal No. 44) engine-ECU <M/T> connector or D-214 (terminal No. 44) engine-A/T-ECU <A/T> connector.
  4. Check and repair harness between B-08 (terminal No. 2) No. 4 ignition coil connector and D-244 (terminal No. 52) engine-ECU <M/T> connector or D-214 (terminal No. 52) engine-A/T-ECU <A/T> connector.
  5. Check and repair harness between B-33 (terminal No. 2) No. 5 ignition coil connector and D-244 (terminal No. 32) engine-ECU <M/T> connector or D-214 (terminal No. 32) engine-A/T-ECU <A/T> connector.
  6. Check and repair harness between B-07 (terminal No. 2) No. 6 ignition coil connector and D-244 (terminal No. 36) engine-ECU <M/T> connector or D-214 (terminal No. 36) engine-A/T-ECU <A/T> connector.

  • Check output line for damage.

Q. Are the check results normal?

Go to Step 11 .
Repair the damaged harness wire.