Ignition System Symptom Diagnosis
IGNITION SYSTEM SYMPTOM DIAGNOSIS CHART
| Condition | Possible Cause | Action |
|---|---|---|
| Engine cranks, but will not start or hard to start | No spark | |
| Blown fuse for ignition coil | Replace . | |
| Loose connection or disconnection of lead wire | Connect securely . | |
| Faulty spark plug(s) | Adjust, clean or replace . | |
| Faulty ignition coil (in ignition coil assembly) | Replace . | |
| Faulty CMP sensor | Replace . | |
| Faulty ECM | Replace . | |
| Maladjusted ignition timing | Adjust . | |
| Poor fuel economy or engine performance | Incorrect ignition timing | Adjust . |
| Faulty spark plug(s) | Adjust, clean or replace . | |
| Faulty ignition coil (in ignition coil assembly) | Replace . | |
| Faulty CMP sensor | Replace . | |
| Faulty ECM | Replace . | |
Reference
Oscilloscope waveforms of CMP sensor (1) and No.1 ignition trigger signal (2) are as shown in figure when connecting oscilloscope between terminals "C46-14" of ECM connectors connected to ECM and ground, and between terminal "C45-4" and ground.
Measurement condition for waveform [A]
WAVEFORMS REFERENCE CHART
| Measurement terminal | CH1: "C45-4" to "C45-6" CH2: "C46-14" to "C45-6" |
| Oscilloscope setting | CH1: 1 V/DID, CH2: 5 V/DID Time: 40 ms/DID |
| Measurement condition | After warmed up engine to normal operating temperature (ECT approx. 95 °C, 203 °F) Engine at 750 r/min. |
Measurement condition for waveform [B]
WAVEFORMS REFERENCE CHART
| Measurement terminal | CH1:"C45-4" to "C45-6" CH2: "C46-14" to "C45-6" |
| Oscilloscope setting | CH1: 1 V/DIV, CH2: 5 V/DIV Time: 1 ms/DIV |
| Measurement condition | After warmed up engine to normal operating temperature (ECT approx. 95 °C, 203 °F) Engine at 750 r/min. |