Ignition System: Testing and Inspection

Ignition Signal Circuit Check

Component Description

Ignition Coil & Power Transistor

The ignition signal from the ECM is sent to and amplified by the power transistor. The power transistor turns ON and OFF the ignition coil primary circuit. This ON/OFF operation induces the proper high voltage in the coil secondary circuit.






Diagnosis Procedure

1. CHECK ENGINE START

Turn ignition switch OFF, and restart engine.

Is engine running?

Yes or No
Yes (With SDT)
GO TO 2.
Yes (Without SDT)
GO TO 3.
No
ERROR! Unknown action!GO TO 4.

2. CHECK OVERALL FUNCTION

With SDT
1 Perform "POWER BALANCE" in "Active test" mode with SDT.
2 Make sure that each circuit produces a momentary engine speed drop.

OK or NG
OK
INSPECTION END
NG
GO TO 10.

3. CHECK OVERALL FUNCTION

Without SDT
1 Let engine idle.
2 Read the voltage signal between ECM terminals 60, 61, 62, 79, 80, 81 and ground with an oscilloscope.





3 Verify that the oscilloscope screen shows the signal wave as shown below.
NOTE:
The pulse cycle changes depending on rpm at idle.






OK or NG
OK
INSPECTION END
NG
GO TO 10.

4. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-I

1 Turn ignition switch OFF, wait at least 10 seconds and then turn it ON.
2 Check voltage between ECM terminals 119, 120 and ground with SDT or tester.











OK or NG
OK
GO TO 5.
NG
Go to [Power Supply and Ground Circuit Check] Power Supply and Ground Circuit Check.

5. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-II

1 Turn ignition switch OFF.
2 Disconnect condenser-1 harness connector.





3 Turn ignition switch ON.
4 Check voltage between condenser-1 terminal 1 and ground with SDT or tester.











OK or NG
OK
GO TO 8.
NG
GO TO 6.

6. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-III

1 Turn ignition switch OFF.
2 Disconnect IPDM E/R harness connector E119.
3 Check harness continuity between IPDM E/R terminal 3 and condenser-1 terminal 1.
Refer to Wiring Diagram.






4 Also check harness for short to ground and short to power.

OK or NG
OK
GO TO 17.
NG
GO TO 7.

7. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors E2, F32
- Harness for open or short between condenser-1 and IPDM E/R


Repair open circuit or short to ground or short to power in harness or connectors.

8. CHECK CONDENSER-1 GROUND CIRCUIT FOR OPEN AND SHORT

1 Turn ignition switch OFF.
2 Check harness continuity between condenser-1 terminal 2 and ground.
Refer to Wiring Diagram.






3 Also check harness for short to power.

OK or NG
OK
GO TO 9.
NG
Repair open circuit or short to power in harness or connectors.

9. CHECK CONDENSER-1

Refer to "Component Inspection".

OK or NG
OK
GO TO 10.
NG
Replace condenser-1.

10. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-V

1 Turn ignition switch OFF.
2 Reconnect all harness connectors disconnected.
3 Disconnect ignition coil harness connector.





4 Turn ignition switch ON.
5 Check voltage between ignition coil terminal 3 and ground with SDT or tester.











OK or NG
OK
GO TO 12.
NG
GO TO 11.

11. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors F26, F225
- Harness for open or short between ignition coil and harness connector F32


Repair or replace harness or connectors.

12. CHECK IGNITION COIL GROUND CIRCUIT FOR OPEN AND SHORT

1 Turn ignition switch OFF.
2 Check harness continuity between ignition coil terminal 2 and ground.
Refer to Wiring Diagram.






3 Also check harness for short to power.

OK or NG
OK
GO TO 14.
NG
GO TO 13.

13. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors F225, F26
- Harness for open or short between ignition coil and ground


Repair open circuit or short to power in harness or connectors.

14. CHECK IGNITION COIL OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1 Disconnect ECM harness connector.
2 Check harness continuity between ECM terminals 60, 61, 62, 79, 80, 81 and ignition coil terminal 1.
Refer to Wiring Diagram.






3 Also check harness for short to ground and short to power.

OK or NG
OK
GO TO 16.
NG
GO TO 15.

15. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors F26, F225
- Harness for open or short between ignition coil and ECM


Repair open circuit or short to ground or short to power in harness or connectors.

16. CHECK IGNITION COIL WITH POWER TRANSISTOR

Refer to "Component Inspection".

OK or NG
OK
GO TO 17.
NG
Replace malfunctioning ignition coil with power transistor. Refer to [Ignition Coil: Exploded View] Exploded View.

17. CHECK INTERMITTENT INCIDENT

Refer to [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.


INSPECTION END

Component Inspection

Ignition Coil with Power Transistor

CAUTION:

Do the following procedure in the place where ventilation is good without the combustible.

1 Turn ignition switch OFF.
2 Disconnect ignition coil harness connector.
3 Check resistance between ignition coil terminals as follows.











4 If NG, Replace ignition coil with power transistor. Refer to [Ignition Coil: Exploded View] Exploded View.
If OK, go to next step.
5 Turn ignition switch OFF.
6 Reconnect all harness connectors disconnected.
7 Remove fuel pump fuse (No.48) in IPDM E/R to release fuel pressure.






NOTE:
Do not use SDT to release fuel pressure, or fuel pressure applies again during the following procedure.

8 Start engine.
9 After engine stalls, crank it two or three times to release all fuel pressure.
10 Turn ignition switch OFF.
11 Remove ignition coil harness connectors to avoid the electrical discharge from the ignition coils.
12 Remove ignition coil and spark plug of the cylinder to be checked.
13 Crank engine for five seconds or more to remove combustion gas in the cylinder.
14 Connect spark plug and harness connector to ignition coil.
15 Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 - 0.66 in) between the edge of the spark plug and grounded metal portion as shown in the figure.





16 Crank engine for about three seconds, and check whether spark is generated between the spark plug and the grounded part.






CAUTION:
- Never place to the spark plug and the ignition coil within 50 cm (19.7 in) each other. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20 kV or more.
- It might cause to damage the ignition coil if the gap of more than 17 mm (0.66 in) is made.

NOTE:
When the gap is less than 13 mm (0.52 in), the spark might be generated even if the coil is malfunctioning.

17 If NG, Replace ignition coil with power transistor.

Condenser-1

1 Turn ignition switch OFF.
2 Disconnect condenser-1 harness connector.
3 Check resistance between condenser-1 terminals 1 and 2.