Identifying Intermittent Conditions

Many intermittent conditions occur with harness or connector movement due to engine torque, rough pavement, vibration or physical movements of a component. Refer to the following for a list of issues that may cause an intermittent condition:

• Moisture and water intrusion in connectors, terminals, and components
• Incomplete connector mating
• Poor terminal contact
• High circuit or component resistance-High resistance can include any resistance, regardless of the amount, which can interrupt the operation of the component.
• Harness that is too short or tight
• Wire insulation that is chaffed or cut
• High or low ambient temperature
• High or low engine coolant temperatures
• High underhood temperatures
• Heat build up in component or circuit due to circuit resistance, poor terminal contact, or high electrical load
• High or low system voltage
• High vehicle load conditions
• Rough road surfaces
• Electro-magnetic interference (EMI)/circuit interference from relays, solenoids or other electrical surge
• Incorrect installation of aftermarket, add on accessories

Visual/Physical Check

• Ensure that the control module grounds are clean, tight, and correctly located. Refer to Power and Grounding Schematic Icons and Power and Grounding Connector End Views .
• Ensure that the vacuum hoses are not split, kinked, and properly connected, as shown on the Vehicle Emission Control Information label. Refer to Emission Hose Routing Diagram .
• Ensure that the air filter is clean and free from restrictions.
• Ensure that there is no water intrusion in connectors terminals and components.
• Inspect the air intake ducts for the following conditions:
  • Collapsed
  • Damaged areas
  • Looseness
  • Incorrect installation
  • Leaking
• Inspect for air leaks at the throttle body mounting area, the mass air flow (MAF) sensor and intake manifold sealing surfaces.
• Inspect the wiring harness for the following conditions:
  • Poor connections
  • Pinches
  • Cuts
• Inspect for loose, damaged, unseated, or missing sensors/components.
• Inspect the terminals for corrosion and correct contact.