Intermittent Failures

Intermittent failures may cause MIL to flicker, or come on and go out after intermittent DTC goes away. However, corresponding DTC will be retained in PCM memory. If related DTC does not reoccur within a certain time frame, related DTC will be erased from PCM memory. Intermittent failures may be caused by a sensor, connector or wiring problems. See INTERMITTENTS in TESTS W/O CODES article.

The PCM also records and stores engine operating conditions when malfunction occurred. This information is referred to as freeze frame data. If malfunction is an engine misfire, or fuel system rich or fuel system lean condition, freeze frame data will be updated with the most current information regarding these failures. Freeze frame data recorded is:

• Fuel System Status
• Load Value (Displayed As Percent)
• Engine Coolant Temperature
• Short Term Fuel Trim (Displayed As Percent)
• Long Term Fuel Trim (Displayed As Percent)
• MAP Vacuum
• Engine RPM
• Vehicle Speed Sensor
• DTC During Data Recording