Monday, November 11, 2019

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2799

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2799

U0136

DTC U0100-U02FF (without HP2)

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.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptor

Refer to Control Module U Code List (See: Diagnostic Trouble Code Descriptions/Control Module U Code List).

Diagnostic Fault Information

Circuit/System Description

The serial data circuit is the means by which the control modules in the vehicle communicate with each other. Once the scan tool is connected to the

serial data circuit through the DLC, the scan tool can be used to monitor each control module for diagnostic purposes and to check for diagnostic

trouble codes (DTCs). When the ignition switch is in RUN, each control module communicating on the serial data circuit sends a state of health

(SOH) message to ensure that the control module is operating properly. When a control module stops communicating on the serial data circuit, for

example if the module loses power or ground, the SOH message it normally sends on the serial data circuit disappears. Other control modules on

the serial data circuit, which expect to receive that SOH message, detect its absence; those control modules in turn set a DTC associated with the

loss of SOH of the non-communicating control module. The DTC is unique to the control module which is not communicating and one or more

control modules may set the same exact code. A loss of serial data communications DTC does not represent a failure of the control modules that

contain the stored code.

Conditions for Running the DTC

The system voltage is between 9-16 V.

Conditions for Setting the DTC

A supervised periodic message that includes the transmitter module availability has not been received.

Action Taken When the DTC Sets

* Specific subsystems will not function.

* DTC U0100 in the TCM will cause the transmission to go into default gears.

* Both DTC U0100 in the TCM and DTC U0101 in the ECM will cause the malfunction indicator lamp (MIL) to illuminate.

Conditions for Clearing the DTC

* The ECM/TCM turns OFF the MIL after 4 consecutive ignition cycles that the diagnostic runs and does not fail.

* A current DTC clears when the malfunction is no longer present.

* A history DTC clears when the control module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1397

2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1397



Reference Information



Schematic Reference



Automatic Transmission Controls Schematics (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Diagrams/Electrical



Diagrams)



Connector End View Reference



Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)



Electrical Information Reference



* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit



Testing/Circuit Testing)



* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic



Procedures/Connector Repairs/Connector Repairs)



* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General



Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)



* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring



Repairs/Wiring Repairs)



Description and Operation



Transmission Component and System Description (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Description and



Operation/AF40-6 - Automatic Transmission/Transmission Component and System Description)



DTC Type Reference



Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code



(DTC) Type Definitions)



Scan Tool Reference



Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information



Circuit/System Verification



1. Ignition On, observe the DTC information with a scan tool. Verify no TCM or communication DTCs are set.



瀚慖f any TCM or communication DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code



Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle) for further diagnosis.



2. Raise the drive wheels.



Caution: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the



vehicle in gear with the wheels hanging down at full travel.



3. Support the lower control arms so that the drive axles are in a horizontal position.



4. Engine running, place the transmission into 2nd gear.



5. Observe the scan tool Vehicle Speed parameter. The following should display a similar vehicle speed once the drive wheels are at a speed



above 5 km/h (3 MPH):



* The scan tool Vehicle Speed parameter



* The odometer



6. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the



conditions that you observed from the Freeze Frame/Failure Records data.



瀚慖f the DTC resets, replace the ECM.



Repair Instructions



Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.



* ECM or TCM-Refer to Control Module References (See: Testing and Inspection/Programming and Relearning) for replacement, setup and



programming.



* Perform the Transmission Adaptive Functions (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Description and



Operation/AF40-6 - Automatic Transmission/Transmission Adaptive Functions).



P0506



DTC P0506, P0507, or P050A (Without LF1, LFW)

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2798

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2798

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General

Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring

Repairs/Wiring Repairs)

Scan Tool Reference

Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information

Circuit/System Verification

Verify that DTC U1814, U2099, B1428, B1370, B1380, B1440, or B1441 is not set.

If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic

Trouble Code (DTC) List - Vehicle).

Circuit/System Testing

Note: Use the schematic to identify the following:

* Control modules the vehicle is equipped with

* Control module locations on the low and high speed GMLAN serial data circuits

* The control modules B+, ignition, ground, communication enable and serial data circuit terminals

1. Determine the control module that is not communicating. Refer to Control Module U Code List (See: Diagnostic Trouble Code

Descriptions/Control Module U Code List).

2. Ignition OFF, disconnect the harness connector of the control module that is not communicating.

3. Test for less than 10 ohm between each ground circuit terminal and ground.

瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.

4. If equipped, verify that a test lamp illuminates between each B+ circuit terminal and ground.

瀚慖f the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test the

control circuits of the control module for a short to ground. If the circuits test normal, replace the control module.

5. If equipped, ignition ON, verify that a test lamp illuminates between each ignition circuit terminal and ground.

瀚慖f the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test

the control circuits of the control module for a short to ground. If the circuits test normal, replace the control module.

Note: Only the high speed GMLAN modules have a serial data communication enable circuit OR an accessory wakeup serial data circuit,

and the BCM is the output for these circuits. Refer to the control module schematics to identify which control modules have these circuits.

6. If equipped, ignition ON, verify that a test lamp illuminates between the communication enable circuit terminal OR the accessory wakeup

circuit terminal and ground.

瀚慖f the test lamp does not illuminate, test the circuit for an open/high resistance. If the circuits test normal, replace the BCM.

7. Ignition OFF for 60 seconds, test for less than 5 ohm between the serial data circuit terminals and the appropriate DLC terminal listed below:

* Class 2 serial data circuit terminal 2

* Low speed GMLAN serial data terminal 1

* High speed GMLAN serial data terminal 6 or 14

瀚慖f greater than the specified range, test the serial data circuit for an open/high resistance between the non communicating control module

and a control module setting the DTC or a serial data splice pack.

8. If all circuits test normal, replace the control module that is not communicating.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* GMLAN Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Wiring Repairs/GMLAN Wiring Repairs)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for control module replacement, setup, and

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2797

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2797

control modules may set the same exact code. A loss of serial data communications DTC does not represent a failure of the control modules that

contain the stored code.

Conditions for Running the DTC

The system voltage is between 9-16 V.

Conditions for Setting the DTC

A supervised periodic message that includes the transmitter module availability has not been received.

Action Taken When the DTC Sets

* Specific subsystems will not function.

* DTC U0100 in the TCM will cause the transmission to go into default gears.

* Both DTC U0100 in the TCM and DTC U0101 in the ECM will cause the malfunction indicator lamp (MIL) to illuminate.

Conditions for Clearing the DTC

* The ECM/TCM turns OFF the MIL after 4 consecutive ignition cycles that the diagnostic runs and does not fail.

* A current DTC clears when the malfunction is no longer present.

* A history DTC clears when the control module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

Diagnostic Aids

* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no

associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are

transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically

after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:

- A control module on the data communication circuit was disconnected while the communication circuit is awake.

- Power to one or more control modules was interrupted during diagnosis.

- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.

- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.

- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.

These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.

* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between

control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a

control module based only on a history U-code.

* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication

issue.

* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system

inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.

* Use Data Link References (See: Powertrain Management/Computers and Control Systems/Information Bus/Testing and Inspection/Initial

Inspection and Diagnostic Overview) to determine if the control module uses high or low speed GMLAN serial data communications.

* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and

the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control

module.

* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,

providing the vehicle is equipped with the control module.

Reference Information

Schematic Reference

* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical

Diagrams)

* Control Module References (See: Testing and Inspection/Programming and Relearning)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views)

Description and Operation

Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information

Bus/Description and Operation)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit

Testing/Circuit Testing)

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2796

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2796

6. If equipped, ignition ON, verify that a test lamp illuminates between the communication enable circuit terminal OR the accessory wakeup

circuit terminal and ground.

瀚慖f the test lamp does not illuminate, test the circuit for an open/high resistance. If the circuits test normal, replace the BCM.

7. Ignition OFF for 60 seconds, test for less than 5 ohm between the serial data circuit terminals and the appropriate DLC terminal listed below:

* Class 2 serial data circuit terminal 2

* Low speed GMLAN serial data terminal 1

* High speed GMLAN serial data terminal 6 or 14

瀚慖f greater than the specified range, test the serial data circuit for an open/high resistance between the non communicating control module

and a control module setting the DTC or a serial data splice pack.

8. If all circuits test normal, replace the control module that is not communicating.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* GMLAN Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Wiring Repairs/GMLAN Wiring Repairs)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for control module replacement, setup, and

programming

U0134

DTC U0100-U02FF (without HP2)

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.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptor

Refer to Control Module U Code List (See: Diagnostic Trouble Code Descriptions/Control Module U Code List).

Diagnostic Fault Information

Circuit/System Description

The serial data circuit is the means by which the control modules in the vehicle communicate with each other. Once the scan tool is connected to the

serial data circuit through the DLC, the scan tool can be used to monitor each control module for diagnostic purposes and to check for diagnostic

trouble codes (DTCs). When the ignition switch is in RUN, each control module communicating on the serial data circuit sends a state of health

(SOH) message to ensure that the control module is operating properly. When a control module stops communicating on the serial data circuit, for

example if the module loses power or ground, the SOH message it normally sends on the serial data circuit disappears. Other control modules on

the serial data circuit, which expect to receive that SOH message, detect its absence; those control modules in turn set a DTC associated with the

loss of SOH of the non-communicating control module. The DTC is unique to the control module which is not communicating and one or more

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2795

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2795

* Some control modules may not have internal protection for specific control circuits and may open a B+ or ignition fuse. If a fuse is open and

the B+ or ignition circuit is not shorted to ground, ensure none of the control circuits are shorted to ground before replacing the control

module.

* This diagnostic can be used for any control module that is not communicating, regardless of the type of serial data circuit it is connected to,

providing the vehicle is equipped with the control module.

Reference Information

Schematic Reference

* Data Communication Schematics (See: Powertrain Management/Computers and Control Systems/Information Bus/Diagrams/Electrical

Diagrams)

* Control Module References (See: Testing and Inspection/Programming and Relearning)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views)

Description and Operation

Data Link Communications Description and Operation (See: Powertrain Management/Computers and Control Systems/Information

Bus/Description and Operation)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit

Testing/Circuit Testing)

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General

Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring

Repairs/Wiring Repairs)

Scan Tool Reference

Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information

Circuit/System Verification

Verify that DTC U1814, U2099, B1428, B1370, B1380, B1440, or B1441 is not set.

If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic

Trouble Code (DTC) List - Vehicle).

Circuit/System Testing

Note: Use the schematic to identify the following:

* Control modules the vehicle is equipped with

* Control module locations on the low and high speed GMLAN serial data circuits

* The control modules B+, ignition, ground, communication enable and serial data circuit terminals

1. Determine the control module that is not communicating. Refer to Control Module U Code List (See: Diagnostic Trouble Code

Descriptions/Control Module U Code List).

2. Ignition OFF, disconnect the harness connector of the control module that is not communicating.

3. Test for less than 10 ohm between each ground circuit terminal and ground.

瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.

4. If equipped, verify that a test lamp illuminates between each B+ circuit terminal and ground.

瀚慖f the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test the

control circuits of the control module for a short to ground. If the circuits test normal, replace the control module.

5. If equipped, ignition ON, verify that a test lamp illuminates between each ignition circuit terminal and ground.

瀚慖f the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit fuse is open, test

the control circuits of the control module for a short to ground. If the circuits test normal, replace the control module.

Note: Only the high speed GMLAN modules have a serial data communication enable circuit OR an accessory wakeup serial data circuit,

and the BCM is the output for these circuits. Refer to the control module schematics to identify which control modules have these circuits.

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2794

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 2794

Circuit/System Description

The serial data circuit is the means by which the control modules in the vehicle communicate with each other. Once the scan tool is connected to the

serial data circuit through the DLC, the scan tool can be used to monitor each control module for diagnostic purposes and to check for diagnostic

trouble codes (DTCs). When the ignition switch is in RUN, each control module communicating on the serial data circuit sends a state of health

(SOH) message to ensure that the control module is operating properly. When a control module stops communicating on the serial data circuit, for

example if the module loses power or ground, the SOH message it normally sends on the serial data circuit disappears. Other control modules on

the serial data circuit, which expect to receive that SOH message, detect its absence; those control modules in turn set a DTC associated with the

loss of SOH of the non-communicating control module. The DTC is unique to the control module which is not communicating and one or more

control modules may set the same exact code. A loss of serial data communications DTC does not represent a failure of the control modules that

contain the stored code.

Conditions for Running the DTC

The system voltage is between 9-16 V.

Conditions for Setting the DTC

A supervised periodic message that includes the transmitter module availability has not been received.

Action Taken When the DTC Sets

* Specific subsystems will not function.

* DTC U0100 in the TCM will cause the transmission to go into default gears.

* Both DTC U0100 in the TCM and DTC U0101 in the ECM will cause the malfunction indicator lamp (MIL) to illuminate.

Conditions for Clearing the DTC

* The ECM/TCM turns OFF the MIL after 4 consecutive ignition cycles that the diagnostic runs and does not fail.

* A current DTC clears when the malfunction is no longer present.

* A history DTC clears when the control module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

Diagnostic Aids

* Sometimes, while diagnosing a specific customer concern or after a repair, you may notice a history U-code present. However, there is no

associated "current" or "active" status. Loss-of- communication U-codes such as these can set for a variety of reasons. Many times, they are

transparent to the vehicle operator and technician, and/or have no associated symptoms. Eventually, they will erase themselves automatically

after a number of fault-free ignition cycles. This condition would most likely be attributed to one of these scenarios:

- A control module on the data communication circuit was disconnected while the communication circuit is awake.

- Power to one or more control modules was interrupted during diagnosis.

- A low battery condition was present, so some control modules stop communicating when battery voltage drops below a certain threshold.

- Battery power was restored to the vehicle and control modules on the communication circuit did not all re-initialize at the same time.

- If a loss-of-communication U-code appears in history for no apparent reason, it is most likely associated with one of the scenarios above.

These are all temporary conditions and should never be interpreted as an intermittent fault, causing you to replace a part.

* A control module may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between

control modules can be temporary with no apparent symptom or complaint; this does not mean the control module is faulty. Do not replace a

control module based only on a history U-code.

* Do not replace a control module reporting a U-code. The U-code identifies which control module needs to be diagnosed for a communication

issue.

* Communication may be available between the BCM and the scan tool with either the low or high speed GMLAN serial data system

inoperative. This condition is due to the BCM using both the low and high speed GMLAN systems.

* Use Data Link References (See: Powertrain Management/Computers and Control Systems/Information Bus/Testing and Inspection/Initial

Inspection and Diagnostic Overview) to determine if the control module uses high or low speed GMLAN serial data communications.