K 2500 Yukon XL 4WD V8-8.1L VIN G (2001)
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Follow the procedure below in order to test terminal contact.
1. Remove the component in question.
2. Visually inspect each side of the connector for signs of contamination. Avoid touching either side of the connector as oil from your skin may be a
source of contamination as well.
3. Visually inspect the terminal bearing surfaces of the flat wire circuits for splits, cracks, or other imperfections that could cause poor terminal
contact. Visually inspect the component side connector 10 ensure that all of the terminals are uniform and free of damage or deformation.
4. Insert the appropriate adapter from the J 42675 Flat Wire Probe Adapter Kit on the flat wire harness connector in order to test the circuit in
question.
Testing For Short to Ground
NOTE: Refer to Test Probe Notice in Cautions and Notices.
The following procedures test for a short to ground in a circuit.
With a DMM
1. Remove the power feed (i.e. fuse, control module) from the suspect circuit.
2. Disconnect the load.
3. Set the rotary dial of the DMM to the position.
4. Connect one lead of the DMM to one end of the circuit to be tested.
5. Connect the other lead of the DMM to a good ground.
6. If the DMM does NOT display infinite resistance (OL), there is a short to ground in the circuit.
With a Test Lamp
1. Remove the power feed (i.e. fuse, control module) from the suspect circuit.
2. Disconnect the load.
3. Connect one lead of the test lamp to battery positive voltage.
4. Connect the other lead of the test lamp to one end of the circuit to be tested.
5. If the test lamp illuminates, there is a short to ground in the circuit.
Fuse Powering Several Loads
1. Review the system schematic and locate the fuse that is open.
2. Open the first connector or switch leading from the fuse to each load.
3. Connect a DMM across the fuse terminals (be sure that the fuse is powered).
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When the DMM displays voltage the short is in the wiring leading to the first connector or switch.
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If the DMM does not display voltage refer to the next step.
4. Close each connector or switch until the DMM displays voltage in order to find which circuit is shorted.
Flat Wire Repairs
NOTE: The flat wire within the flex wiring harness is not serviceable. If an open or short exists within the flex wiring harness the complete harness
must be replaced.
Heated Oxygen Sensor (HO2S) Wiring Repairs
NOTE: Do not solder repairs under any circumstances as this could result in the air reference being obstructed.
If the heated oxygen sensor pigtail wiring, connector, or terminal is damaged the entire oxygen sensor assembly must be replaced. Do not attempt to
repair the wiring, connector, or terminals. In order for the sensor to function properly it must have a clean air reference. This clean air reference is
obtained by way of the oxygen sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of
the air reference and degrade oxygen sensor performance.
The following guidelines should be used when servicing the heated oxygen sensor:
Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor, causing poor
performance. Also, the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path
for foreign materials to enter the sensor and cause performance problems.
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Neither the sensor nor vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the
lead wire.
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Do not remove or defeat the oxygen sensor ground wire (where applicable). Vehicles that utilize the ground wire sensor may rely on this ground as
the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance.
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To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector.
The engine harness may be repaired using the J 38125-B.
Repairing Damaged Wire Insulation