U2611
DTC U2611
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC U2611
- Auxiliary Transmission Fluid Pump Control Module Lost Communication with Hybrid Powertrain Control Module
For symptom byte information, refer to Symptom Byte List Symptom Byte List.
Circuit/System Description
The Auxiliary Transmission Fluid Pump Control Module and the Hybrid Powertrain Control Module 1 are all internal to the Power Inverter Module. The Auxiliary Transmission Fluid Pump Control Module communicates only with the Hybrid Powertrain Control Module 1 with the Hybrid Powertrain Control Module 1 sending out diagnostic trouble code information to other devices regarding the Auxiliary Transmission Fluid Pump Control Module. All circuits to the Hybrid Powertrain Control Module 1 and Auxiliary Transmission Fluid Pump Control Module are also internal to the Power Inverter Module and replaced as a single component.
Communication diagnostics for the serial data, including device power and ground as well as the wakeup circuits for Auxiliary Transmission Fluid Pump Control Module and the Hybrid Powertrain Control Module 1 are all diagnosed from external sources only to the Power Inverter Module connector because any circuit fault condition within the Power Inverter Module will cause a complete replacement.
Conditions for Running the DTC
* The system voltage is more than 10 V.
* The vehicle power mode master requires serial data communication to occur from this specific device.
Conditions for Setting the DTC
A supervised periodic message that includes the transmitter device availability has not been received.
Action Taken When the DTC Sets
The device is never signaled. Therefore, the specific subsystems will not function.
Conditions for Clearing the DTC
* A current DTC clears when the malfunction is no longer present.
* A history DTC clears when the device 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 device on the data communication circuit was disconnected while the communication circuit is awake.
- Power to one or more devices was interrupted during diagnosis.
- A low battery condition was present, so some devices stop communicating when battery voltage drops below a certain threshold.
- Battery power was restored to the vehicle and devices 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 device may have a U-code stored in history that does not require any repairs. Issues with late or corrupted messages between devices can be temporary with no apparent symptom or complaint; this does not mean the device is faulty. Do not replace a device based only on a history U-code.
* The device 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 non communicating device.
* If DTC U2611 is only set current in the Hybrid Powertrain Control Module 1, the Power Inverter Module must be replaced due to all circuits between the Hybrid Powertrain Control Module 1 and Auxiliary Transmission Fluid Pump Control Module being internal to the Power Inverter Module.
Reference Information
Schematic Reference
* Data Communication Schematics [1][2]Electrical Diagrams
* Control Module References Programming and Relearning
Connector End View Reference
Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation
Data Link Communications Description and Operation Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
1. Vehicle in Service Mode.
2. Verify that DTC U0293 is not set.
• If DTC U0293 is set
Refer to DTC U0100-U02FF U0100.
• If DTC U0293 is not set
3. Verify that DTC U2611 is not set current only in the K114A Hybrid Powertrain Control Module 1.
• If DTC U2611 is set
Replace the T6 Power Inverter Module.
• If DTC U2611 is not set
4. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* GMLAN Wiring Repairs GMLAN Wiring Repairs
* Control Module References Programming and Relearning for device replacement, programming and setup