Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Procedure
- CHECK ENGINE START
Turn ignition switch OFF, and restart engine.
Is engine running?
Yes or No
- CHECK OVERALL FUNCTION
With CONSULT-II
- Perform POWER BALANCE in ACTIVE TEST mode with CONSULT-II.
- Make sure that all circuits do not produce a momentary engine speed drop.
OK or NG
- OK: INSPECTION END
- NG: GO TO 14 .
- CHECK OVERALL FUNCTION
Without CONSULT-II
- Let engine idle.
- Read the voltage signal between ECM terminals 5, 6, 7, 15, 16, 17 and ground with oscilloscope.
- Verify that the oscilloscope screen shows the signal wave as shown in Fig 2 below.
OK or NG
- OK: INSPECTION END
- NG: GO TO 14 .
- CHECK IGNITION COIL POWER SUPPLY CIRCUIT-I
- Turn ignition switch ON.
- Check voltage between ECM terminals 110, 112 and ground with CONSULT-II or tester.
Voltage: Battery Voltage
OK or NG
- OK: GO TO 5.
- NG: Go to TROUBLE DIAGNOSIS FOR POWER SUPPLY .
- CHECK IGNITION COIL POWER SUPPLY CIRCUIT-II
- Check voltage between ECM terminal 31 and ground with CONSULT-II or tester.
Voltage: Battery Voltage
OK or NG
- OK: GO TO 11 .
- NG: GO TO 6.
- CHECK IGNITION COIL POWER SUPPLY CIRCUIT-III
- Turn ignition switch OFF.
- Disconnect ECM relay. See Figure .
- Check harness continuity between ECM relay terminal 31 and ECM relay terminal 7. Refer to Wiring Diagram.
Continuity should exist.
- Also check harness for short to ground and short to power.
OK or NG
- OK: GO TO 8 .
- NG: GO TO 7.
- DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E15, F18
- Harness for open or short between ECM and ECM relay
OK or NG
- : Repair open circuit or short to ground or short to power in harness or connectors.
- CHECK IGNITION COIL POWER SUPPLY CIRCUIT-IV
Check voltage between ECM relay terminal 6 and ground with CONSULT-II or tester.
OK or NG
- OK: GO TO 10 .
- NG: GO TO 9.
- DETECT MALFUNCTIONING PART
Check the following.
- 15A fuse
- Harness for open and short between ECM relay and fuse
OK or NG
- : Repair or replace harness or connectors.
- CHECK ECM RELAY
- Apply 12V direct current between ECM relay terminals 1 and 2.
- Check continuity between ECM relay terminals 3 and 5, 6 and 7.
OK or NG
- OK: GO TO 19 .
- NG: Replace ECM relay.
- CHECK CONDENSER CIRCUIT FOR OPEN AND SHORT
- Turn ignition switch OFF.
- Disconnect condenser harness connector.
- Check harness continuity between ECM terminal 31 and condenser terminal 1.
- Refer to Wiring Diagram.
Continuity should exist.
- Also check for short to ground and short to power.
OK or NG
- OK: GO TO 12.
- : Repair open circuit or short to ground or short to power in harness or connectors.
- CHECK CONDENSER GROUND CIRCUIT FOR OPEN AND SHORT
- Check harness continuity between condenser terminal 2 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
- Also check harness for short to power.
OK or NG
- OK: GO TO 13.
- NG: Repair open circuit or short to power in harness or connectors.
- Check harness continuity between condenser terminal 2 and engine ground. Refer to Wiring Diagram.
- CHECK CONDENSER
Check resistance between condenser terminals 1 and 2.
OK or NG
- OK: GO TO 14.
- NG: Replace condenser.
- CHECK IGNITION COIL POWER SUPPLY CIRCUIT-V
- Turn ignition switch OFF.
- Reconnect harness connectors disconnected.
- Disconnect ignition coil harness connector.
- Turn ignition switch ON.
- Check voltage between ignition coil terminal 3 and ground with CONSULT-II or tester.
OK or NG
- OK: GO TO 16 .
- NG: GO TO 15.
- DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors F57, F221
- Harness for open and short between ignition coil and harness connector F18
- : Repair or replace harness or connectors.
- CHECK IGNITION COIL GROUND CIRCUIT FOR OPEN AND SHORT
- Turn ignition switch OFF.
- Check harness continuity between ignition coil terminal 2 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
- Also check harness for short to power.
OK or NG
- OK: GO TO 17.
- NG: Repair open circuit or short to power in harness or connectors.
- CHECK IGNITION COIL OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
- Disconnect ECM harness connector.
- Check harness continuity between ECM terminals 5, 6, 7, 15, 16, 17 and ignition coil terminal 1.
Refer to Wiring Diagram.
Continuity should exist.
- Also check harness for short to ground and short to power.
OK or NG
- OK: GO TO 18.
- NG: Repair open circuit or short to ground or short to power in harness or connectors.
- CHECK IGNITION COIL WITH POWER TRANSISTOR
Check resistance between ignition coil terminals 2 and 3.
OK or NG
- OK: GO TO 19.
- NG: Replace ignition coil with power transistor.
- CHECK INTERMITTENT INCIDENT
Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .
- : INSPECTION END
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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