Escalade EXT AWD V8-6.2L (2009)
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.
Duplicating Failure Conditions
*
If none of the previous tests are successful, attempt to duplicate and/or capture the failure conditions.
*
Freeze Frame/Failure Records data, where applicable, contains the conditions that were present when the DTC set.
1. Review and record Freeze Frame/Failure Records data.
2. Clear the DTCs using the scan tool.
3. Turn the key to OFF and wait 15 seconds.
4. Operate the vehicle under the same conditions that were noted in Freeze Frame/Failure Records data, as closely as possible. The vehicle must
also be operating within the Conditions for Running the DTC. Refer to Conditions for Running the DTC in the supporting text if a DTC is
being diagnosed.
5. Monitor DTC Status for the DTC being tested. The scan tool will indicate Ran, when the enabling conditions have been satisfied long enough
for the DTC to run. The scan tool will also indicate whether the DTC passed or failed.
*
An alternate method is to drive the vehicle with the DMM connected to a suspected circuit. An abnormal reading on the DMM when the concern
occurs, may help you locate 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.
3. Connect the positive lead of the DMM to the circuit to be tested.
4. Connect the negative lead of the DMM to a good ground.
5. Press the Hz button on the DMM.
6. The DMM will display the frequency measured.
Measuring Voltage
Measuring Voltage
Danger: Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:
*
Safety glasses with appropriate side shields when within 50 feet of the vehicle, either indoors or outdoors
*
Certified and up-to-date Class "0"Insulation gloves rated at 1000V with leather protectors
-
Visually and functionally inspect the gloves before use.
-
Wear the Insulation gloves at all times when working with the high voltage battery assembly, whether the system is energized or not.
