Tahoe 4WD V8-6.2L (2009)
6. Disconnect the harness connector at the JX 200 splice pack.
7. Test for less than 2 ohmbetween the serial data circuit terminal 1 and the JX 200 splice pack terminal D.
‹› If greater than the specified range, test the serial data circuit for an open/high resistance. If the circuits test normal, replace the splice pack.
Testing the Serial Data Circuits for a Short to Voltage
1. Ignition OFF, disconnect the harness connectors at the JX 200, JX 300, and JX 201 splice packs, as equipped.
2. Ignition ON, test for less than 4.5 V between the DLC serial data circuit terminal 1 and ground.
‹› If greater than the specified range, repair the short to voltage.
3. Test for less than 4.5 V between each serial data circuit and ground.
‹› If greater than the specified range, perform the appropriate test listed below:
*
Serial data circuits with one control module, test the serial data circuit for a short to voltage. If the circuit tests normal replace the control
module.
*
Serial data circuits with 2 or more control modules, test each section of the serial data circuit for a short to voltage. If the circuits test normal,
replace the control module that causes the short to voltage when connected.
Testing the Serial Data Circuits for a Short to Ground
1. Ignition OFF, disconnect the harness connectors at the JX 200, JX 300, and JX 201 splice packs, as equipped.
2. Test for infinite resistance between the DLC serial data circuit terminal 1 and ground.
‹› If not the specified value, repair the short to ground.
3. Ignition OFF for 60 seconds, test for greater than 100 ohmbetween each serial data circuit and ground.
‹› If less than the specified range, perform the appropriate test listed below:
*
Serial data circuits with one control module, test the serial data circuit for a short to ground. If the circuit tests normal replace the control
module.
*
Serial data circuits with 2 or more control modules, test each section of the serial data circuit for a short to ground. If the circuits test normal,
replace the control module that causes the short to ground when connected.
Testing the Serial Data Circuit for an Open/High Resistance
1. If equipped with a JX 300 splice pack, ignition ON, verify the scan tool communicates with one or more control modules connected to the JX 300
splice pack.
‹› If all control modules on the JX 300 spice pack do not communicate, test the serial data circuit between the JX 200 and JX 300 splice packs
for an open/high resistance. If the circuit tests normal, test each splice pack for an open/high resistance.
2. Ignition OFF, disconnect one of the harness connectors listed below:
*
JX 200 if the control modules not communicating are connected to the JX 200 splice pack
*
JX 201 if the control modules not communicating are connected to the JX 201 splice pack, if equipped
*
JX 300 if the control modules not communicating are connected to the JX 300 splice pack
3. Install a 3A fused jumper wire between the disconnected splice pack terminal 1 and a low speed GMLAN serial data circuit that is not
communicating.
4. Ignition ON, verify the scan tool communicates with the control modules connected to the low speed GMLAN serial data circuit.
‹› If any control module does not communicate, test each section of the serial data circuit for an open/high resistance. If the circuits test normal,
replace the control module that does not communicate when connected.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Testing and Inspection/Diagnostic Trouble Code Tests and Associated Procedures/Verification Tests
and Procedures) after completing the repair.
*
GMLAN Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics)
*
Control Module References (See: Testing and Inspection/Programming and Relearning) for module replacement, setup, and programming
Scan Tool Does Not Power Up
