锟斤拷 If not within the specified range, perform the Circuit/System Testing.
2. Observe the scan tool Object Sensor Supply Voltage parameter while pressing and releasing the B71R liftgate object sensor - right. The
reading should change from Inactive to Active as the sensor is pressed and released.
锟斤拷 If the value does not change, test or replace the B71R liftgate object sensor - right.
3. Observe the scan tool Object Sensor Supply Voltage parameter while pressing and releasing the B71L liftgate object sensor - left. The reading
should change from Inactive to Active as the sensor is pressed and released.
锟斤拷 If the value does not change, test or replace the B71L liftgate object sensor - left.
4. Command the liftgate to power close by pressing the B70 liftgate close switch and as the liftgate is closing, press the B71R liftgate object
sensor - right or the B71L liftgate object sensor - left. The liftgate should stop and power open.
锟斤拷 If the liftgate continues to power close, replace the K39 liftgate module.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the B71R liftgate object sensor - right.
2. Test for less than 10 ohm between the low reference circuit terminal B and ground.
锟斤拷 If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal,
replace the K39 liftgate module.
3. Disconnect the harness connector at the B71L liftgate object sensor - left.
4. Ignition ON, test for 4.75-5.25 V between the signal circuit terminal A and ground.
锟斤拷 If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the
K39 liftgate module.
锟斤拷 If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K39 liftgate module.
5. Test of infinite resistance between the signal circuit terminal B and ground.
锟斤拷 If not the specified value, test the signal circuit for a short to ground.
6. Test for less than 10 ohm between the signal circuit terminal A at the B71R liftgate object sensor - right and the signal circuit terminal B at the
B71L liftgate object sensor - left.
锟斤拷 If greater than the specified range, test the signal circuit for an open/high resistance.
7. If all circuits test normal, test or replace the appropriate B71 liftgate object sensor.
Component Testing
1. Ignition OFF, disconnect the harness connector at the appropriate B71 liftgate object sensor.
2. Test for 8K-12K ohm between the signal terminal A and the low reference terminal B.
锟斤拷 If not within the specified range, replace the B71 liftgate object sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Liftgate Side Upper Sensor Replacement (Except Avalanche and EXT Escalade) (See: Body and Frame/Doors, Hood and Trunk/Trunk /
Liftgate/Trunk / Liftgate Position Sensor/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for the liftgate module replacement, setup and
programming
B0158
DTC B0158, B0163, B0168, B0173, B0178, B0509, B0514, B3578, or B3583
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
