Outline Of Diagnosis

Detect whether the misfire occurred or not. (Revolution fluctuation method) Monitoring the misfire which influences exhaust deterioration (1.5 times of FTP) and catalyst damage is made obligatory by the law. Misfire affecting these two has three patterns below.

• Intermittent misfire (The same cylinder misfires in random, or different cylinders misfire in random.): FTP 1.5 times misfire
• Every time misfire (The same cylinder misfires every time.): FTP 1.5 times misfire, Catalyst damage misfire The following detecting methods are adopted for these detection.

1. Intermittent misfire: FTP 1.5 times misfire
   • 180°Interval Difference Method (MT: 1,800 RPM or less; AT: None)
   • 360° Interval Difference Method (whole range)
   • 720°Interval Difference Method (3,000 RPM or less)
2. Every time misfire: FTP 1.5 times misfire, Catalyst damage misfire
   • 360° Interval Difference Method