Vibe FWD L4-1.8L (2010)
*
Disconnecting a connector and reconnecting
*
Stressing the mechanical connection of a connector
*
Pulling on the harness or wire in order to identify a separation/break inside the insulation
*
Relocating a harness or wires
All these actions should be performed with some goal in mind. For instance, with a scan tool connected, wiggling the wires may uncover a faulty input to
the control module. The snapshot option would be appropriate here. Refer to Scan Tool Snapshot Procedure (See: Testing and Inspection/Component
Tests and General Diagnostics/Circuit Testing/Scan Tool Snapshot Procedure). You may need to load the vehicle in order to duplicate the concern. This
may require the use of weights, floorjacks, jackstands, frame machines, etc. In these cases you are attempting to duplicate the concern by manipulating
the suspension or frame. This method is useful in finding harnesses that are too short and their connectors pull apart enough to cause a poor connection.
A DMM set to Peak Min/Max mode and connected to the suspect circuit while testing can yield desirable results. Refer to Testing for Electrical
Intermittents (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Testing for Electrical Intermittents).
Certainly, using the senses of sight, smell, and hearing while manipulating the circuit can provide good results as well.
There may be instances where circuit manipulation alone will not meet the required criteria for the fault condition to appear. In such cases it may be
necessary to expose the suspect circuit to other conditions while manipulating the harness. Such conditions would include high moisture conditions,
along with exceptionally high or low temperatures. The following discusses how to expose the circuit to these kinds of conditions.
Salt Water Spray
Some compounds possess the ability to conduct electricity when dissolved in water such as ordinary salt. By mixing table salt with water in sufficient
quantities, you can enhance the conductive properties of water so that any circuit which may be sensitive to moisture will more readily fail when liberally
sprayed with this mixture.
Mixing 0.35L (12 oz) of water with approximately 1 tablespoon of salt will yield a salt solution of 5 percent. Fill a normal spray bottle with this mixture.
This mixture is sufficient to enhance the water's own conductivity. This may cause the circuit to fail more easily when sprayed. Once the mixture is
completed, spray the suspect area liberally with the solution. Then, while monitoring either a scan tool or DMM, manipulate the harness as discussed
previously.
High Temperature Conditions
Tools Required
J 25070 Heat Gun
If the complaint tends to be heat related, you can simulate the condition using the J 25070 .
Using the heat gun, you can heat up the suspected area or component. Manipulate the harnesses under high temperature conditions while monitoring the
scan tool or DMM to locate the fault condition.
The high temperature condition may be achieved simply by test driving the vehicle at normal operating temperature. If a heat gun is unavailable, consider
this option to enhance your diagnosis. This option does not allow for the same control, however.
Low Temperature Conditions
Depending on the nature of the fault condition, placing a fan in front of the vehicle while the vehicle is in the shade can have the desired effect.
If this is unsuccessful, use local cooling treatments such as ice or a venturi type nozzle (one that provides hot or cold air). This type of tool is capable of
producing air stream temperatures down to -18°C (0°F) from one end and 71°C (160°F) from the other. This is ideally suited for localized cooling needs.
Once the vehicle, component, or harness has been sufficiently cooled, manipulate the harness or components in an effort to duplicate the concern.
Measuring Frequency
Measuring Frequency
Caution: Refer to Test Probe Caution (See: Service Precautions/Vehicle Damage Warnings/Test Probe Caution).
The following procedure determines the frequency of a signal.
Note: Connecting the DMM to the circuit before pressing the Hz button will allow the DMM to autorange to an appropriate range.
1. Apply power to the circuit.
2. Set the rotary dial of the DMM to the V (AC) position.
