Intermittents/History Codes/Poor Connections

History codes are those indicating that the SDM has previously detected a fault which has since disappeared. Most intermittents are caused by faulty electrical connections or wiring. Some items to check are:

• Poor mating of connector halves, or terminals not fully seated in the connector body (backed out).
• Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact.
• Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal from Connector Test Adaptor Kit (SA 9206Z) to check for proper tension. See "Checking Terminal Contact" in this section.
  CAUTION: Connector Test Adaptor Kit (SA 9206Z) must be used whenever a diagnostic procedure requests checking or probing a terminal. This will ensure that no damage to the terminal will occur.
• Poor terminal-to-wire connection. Checking this requires removing the terminal from the connector. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over the wire insulation rather than the wire itself and corrosion in the wire to terminal contact area, etc.
• Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of vehicle.
• Wiring broken inside the insulation. This condition would cause a resistance to show continuity, but if only one or two strands of wire are intact, resistance would be too high.

To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined in WIRE REPAIR .