Envoy, Rainer, Trailblazer 2006-2007

4.2L L6 VIN S Auto 9

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Trouble Code: P2A01



HO2S Performance Sensor 2

Trouble Code: U0001



High Speed CAN Communication Bus

Possible Causes:



This DTC cannot be retrieved with a current status. Diagnosis of current DTC is accomplished via the symptom, Scan Tool Does Not Communicate with GMLAN Device. Refer to Scan Tool Does Not Communicate with High Speed GMLAN Device .
 
An intermittent condition is likely to be caused by a short on the GMLAN serial data circuits. Use the Scan Tool Does Not Communicate with GMLAN Device procedure in order to isolate an intermittent condition. Refer to Scan Tool Does Not Communicate with High Speed GMLAN Device .
 

Trouble Code: U0073



Controller Area Network (CAN) Bus Communication

Possible Causes:



This DTC cannot be retrieved with a current status. Diagnosis of a current DTC is accomplished via the symptom, Scan Tool Does Not Communicate with High and/or Low Speed GMLAN Device. Refer to Data Link References for the correct procedure for the specific module(s) and the busses they use to communicate.
 
An intermittent condition is likely to be caused by a short on the GMLAN serial data circuits. Use the Scan Tool Does Not Communicate with High and/or Low Speed GMLAN Device procedure in order to isolate an intermittent condition. Refer to Data Link References for the correct procedure for the specific modules.
 

Trouble Code: U0073



High Speed Communication Bus

Possible Causes:



An intermittent condition is likely to be caused by a short on the high speed GMLAN serial data circuits.
 
This DTC cannot be retrieved with a current status. Diagnosis is accomplished using the symptom Scan Tool Does Not Communicate with High Speed GMLAN Device .
 
Refer to Data Link References for the specific modules using high speed GMLAN serial data.
 

Trouble Code: U0100



Lost Communication With Engine/Powertrain Control Module (ECM/PCM)

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 

Trouble Code: U0100



Lost Communication With Engine Control Module (ECM)

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 

Trouble Code: U0101



Lost Communication With Transmission Control Module (TCM)

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 

Trouble Code: U0101



Lost Communication With Transmission Control Module (TCM)

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 

Trouble Code: U0140



Lost Communication With Body Control Module

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 

Trouble Code: U0151



Lost Communication With Restraints Control Module

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 

Trouble Code: U0155



Lost Communication With Instrument Panel Cluster (IPC) Control Module

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 

Trouble Code: U0184



Lost Communication With Radio

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 

Trouble Code: U0299



N/A

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 

Trouble Code: U0299



N/A

Possible Causes:



A poor connection at the inoperative module may cause this code to set.
 
An improperly powered module may cause this code to set.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 

Trouble Code: U1000



Class 2 Communication Malfunction

Possible Causes:



When a malfunction occurs while modules are communicating, a lost communication DTC is set as a current DTC. When the modules stop communicating the current lost communication DTC is cleared but the history DTC remains. When the modules begin to communicate again, the module with the open fuse will not be learned by the other modules so U1000 is set current by the other modules. If the malfunction occurs when the modules are not communicating, only U1000 is set.
 

Trouble Code: U1000



Class 2 Data Link Malfunction

Possible Causes:



When a malfunction occurs while modules are communicating, a lost communication DTC is set as a current DTC. When the modules stop communicating the current lost communication DTC is cleared but the history DTC remains. When the modules begin to communicate again, the module with the open fuse will not be learned by the other modules so U1000 is set current by the other modules. If the malfunction occurs when the modules are not communicating, only U1000 is set.
 

Trouble Code: U1001



Lost Communication with XXX

Possible Causes:



An intermittent open between a module and a star connector may cause this DTC to set.
 
A poor connection at a module or a star connector may cause this DTC to set.
 
An intermittent open in a star connector may cause this DTC to set.
 
An open voltage or ground circuit to a module may cause this DTC to set.
 
An internal module malfunction may cause this DTC to set.
 

Trouble Code: U1001



Lost Communication with XXX

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1016



Lost Communication With ECM/PCM

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1017



Lost Communication With Engine Control Module

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1024



Lost Communication With Transmission Control Module

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1026



Lost Communication With ATC/TCCM

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1040



Lost Communication With Electronic Brake Control Module

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1041



Lost Communication With Electronic Brake Control Module

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1064



Lost Communication With Body Control Module (BCM)

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1088



Lost Communication With Sensing and Diagnostic Module (SDM)

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1096



Loss of IPC Communications

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1097



Loss of DIC Communications

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1098



Loss of HUD Communications

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1099



Loss of HUD Communications

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1111



Lost Communication With Chime Module

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1128



Loss of IRC Communications

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1129



Loss of AMP Communications

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1133



Lost Communication With DVD Player

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1137



Lost Communication With Digital Radio Receiver

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1144



Loss of PHN Communications

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1147



Lost Communication With Onstar

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1151



Lost Communication With Onstar

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1152



Lost Communications With HVAC Control System

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

Trouble Code: U1153



Lost Communication With Climate Control Panel

Possible Causes:



Use the DTC Descriptor list above to determine the module which is not communicating.
 
Some modules may not have internal protection for specific voltage outputs and may open a battery positive voltage or ignition voltage source fuse. If a voltage input fuse is open and no short is found in that circuit, ensure that no module output voltage circuit is shorted to ground before replacing the module.
 
This diagnostic can be used for any module that should communicate with Class 2 serial data providing the vehicle is equipped with the option that uses that module.
 

 
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