2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3005

2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 3005

1. Attempt to communicate with all control modules on the Powertrain High Speed GMLAN serial data circuit, refer to. Communications

should not be available with two or more control modules on the Powertrain High Speed GMLAN serial data circuit.

瀚慖f only one control module is not communicating, diagnose that control module only; refer to.

2. Disconnect the scan tool from the DLC. The following tests will be done at the DLC connector.

3. Ignition ON, test for less than 4.5 V between the serial data circuits listed below and ground:

* Terminal 3

* Terminal 11

瀚慖f greater than the specified range, test the serial data circuit for a short to voltage; refer to Testing the Serial Data Circuits for a Short to

Voltage.

4. Ignition OFF for 60 seconds, test for greater than 100 ohm between the serial data circuit listed below and ground:

* Terminal 3

* Terminal 11

瀚慖f not the specified value, test the serial data circuit for a short to ground; refer to Testing the Serial Data Circuits for a Short to ground.

5. Test for 50-70 ohm between the serial data circuit terminal 3 and terminal 11.

瀚慖f less than 35 ohm, test for a short between the serial data circuits; refer to Testing the Serial Data Circuits for a Short between the

Circuits.

瀚慖f 35-50 ohm there may be a third terminating resistor between the serial data circuits. This can happen if the incorrect control module is

installed. Some control modules are available with and without the terminating resistors installed to reduce the need of terminating

resistors in the wiring harness.

瀚慖f greater than 70 ohm but less than infinite, test the serial data circuit for an open/high resistance; refer to Testing the Serial Data Circuits

for an Open/High Resistance.

瀚慖f infinite, test the serial data circuits between the DLC and the first connection to the serial data circuit for an open/high resistance.

Testing the Serial Data Circuits for a Short to Voltage

1. Ignition OFF, disconnect the harness connectors with the Powertrain High Speed GMLAN serial data circuits at an easily accessible control

module.

2. Ignition ON, test for greater than 4.5 V between each serial data circuit at the control module connector that was just disconnected and

ground. Verify that one or more serial data circuits are greater than 4.5 V.

瀚慖f all serial data circuits are less than the specified range, replace the control module that was disconnected.

3. Ignition OFF, disconnect the harness connectors with the Powertrain High Speed GMLAN serial data circuits at another control module, in

the direction of the circuit shorted to voltage.

4. Ignition ON, test for greater than 4.5 V between the serial data circuits at the control module connector that was just disconnected and

ground. Verify that one or more serial data circuits are greater than 4.5 V.

瀚慖f all serial data circuits are less than the specified range, replace the control module that was just disconnected.

5. Repeat step 3 until one of the follow conditions are isolated:

* A short to voltage on the serial data circuit between 2 control modules

* A short to voltage on the serial data circuit between a control module and a terminating resistor.

Testing the Serial Data Circuits for a Short to Ground

1. Ignition OFF, disconnect the harness connectors with the Powertrain High Speed GMLAN serial data circuits at an easily accessible control

module.

2. Ignition OFF for 60 seconds, test for less than 1k ohm between each serial data circuit at the control module connector that was just

disconnected and ground. Verify that one or more serial data circuits are less than 1k ohm.

瀚慖f all serial data circuits are greater than the specified range, replace the control module that was disconnected.

3. Disconnect the harness connectors with the Powertrain High Speed GMLAN serial data circuits at another control module, in the direction of

the circuit shorted to ground.

4. Ignition OFF for 60 seconds, test for less than 1k ohm between the serial data circuits at the control module connector that was just

disconnected and ground. Verify that one or more serial data circuits are less than 1k ohm.

瀚慖f greater than the specified range for all serial data circuits, replace the control module that was just disconnected.

5. Repeat step 3 until one of the follow conditions are isolated: