Symptom Related Diagnostic Procedures

Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. 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 to check for proper tension. Refer to "Checking Terminal Contact" in this section.
^ The J 35616 Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the test adapter will ensure that no damage to the terminal will occur.
^ Poor terminal-to-wire connection. Checking this requires removing the terminal from the connector body. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wiring insulation rather than the wire itself, 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 the vehicle.
^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi- strand-type wire are intact, resistance could be far too high. This is of particular importance in the PASS-Key(R) detection circuit, in which resistance is critical.

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

Checking Terminal Contact

When diagnosing an electrical system that utilizes Metri-Pack 1501280/4801630 series terminals (refer to Terminal Repair Kit J 38125-A instruction manual J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component.

Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal:

Frequently, a diagnostic chart leads to a step that reads: "Check for poor connection". Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation.

Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually to underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit.

Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact causing an open or intermittently open circuit.

Follow the procedure below to check terminal contact.

1. Separate the connector halves, refer to Terminal Repair Kit J 38125-A instruction manual J 38125-4.
2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing high terminal resistance, intermittent connection or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety, terminals, seals and connector body.
3. Using an equivalent male terminal from the Terminal Repair Kit J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals.
4. Using an equivalent female terminal from the Terminal Repair Kit J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question, using a terminal from Terminal Repair Kit J 38125-A.

If a visual (physical) check does not find the cause of the problem, the vehicle can be driven with a voltmeter connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit.In the case of the circuits which can be monitored by using the CCM's on-board diagnostic capabilities, these may be monitored for abnormal voltages, counts, etc. which occur at the same time the problem occurs, possibly indicating a problem with that circuit.