Sierra, Silverado 2006-2007

4.8L V8 VIN V Auto 12

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Trouble Code: P2636



Fuel Transfer Pump Flow Insufficient

Trouble Code: P2670



Actuator Supply Voltage 2 Low

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P2671



Actuator Supply Voltage 2 High

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P268A



Fuel Injector Calibration Data Not Programmed

Trouble Code: P2714



Clutch Pressure Control (PC) Solenoid 4 - Stuck Off

Possible Causes:



When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions.
 

Trouble Code: P2715



Clutch Pressure Control (PC) Solenoid 4 - Stuck On

Possible Causes:



When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions.
 

Trouble Code: P2719



Clutch Pressure Control (PC) Solenoid 4 System Performance

Possible Causes:



When attempting to set solenoid electrical DTCs, ensure the TCM is warmed up and the transmission is operated in second gear long enough to ensure a 3°C (5°F) increase in TCM substrate temperature. This will place the TCM under the optimal conditions to test solenoid electrical DTCs.
 

Trouble Code: P2720



Clutch Pressure Control (PC) Solenoid 4 Control Circuit Low Voltage

Possible Causes:



When attempting to set solenoid electrical DTCs, ensure the TCM is warmed up and the transmission is operated in second gear long enough to ensure a 3°C (5°F) increase in TCM substrate temperature. This will place the TCM under the optimal conditions to test solenoid electrical DTCs.
 

Trouble Code: P2721



Clutch Pressure Control (PC) Solenoid 4 Control Circuit High Voltage

Possible Causes:



When attempting to set solenoid electrical DTCs, ensure the TCM is warmed up and the transmission is operated in second gear long enough to ensure a 3°C (5°F) increase in TCM substrate temperature. This will place the TCM under the optimal conditions to test solenoid electrical DTCs.
 

Trouble Code: P2723



Pressure Control Solenoid 1 (PCS1) Controlled Clutch Stuck Off

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.This DTC indicates the on-coming clutch being controlled by PCS1 is not applied or applied too slowly. This could indicate a leak or obstruction in a specific clutch apply circuit. Observe scan tool failure record data for previous or current range information when the DTC was set, in order to determine the specific shift when the DTC was set. Refer to the Solenoid and Clutch Chart to determine which clutch circuit is suspect.Important: Clutch failure due to installation of an engine power upgrade is not covered under the manufacturers warranty. Inspect for the presence of an add-on engine power package. When engine horsepower or torque is increased over factory rating, a shift flare condition may occur.
 

Trouble Code: P2724



Pressure Control Solenoid 1 (PCS1) Controlled Clutch Stuck On

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.This DTC indicates the off-going clutch being controlled by PCS1 is not releasing or is slow to release. This could indicate a leak or obstruction in a specific clutch apply circuit. Observe scan tool failure record data for previous or current range information when the DTC was set, in order to determine the specific shift when the DTC was set. Refer to the Solenoid and Clutch Chart to determine which clutch circuit is suspect.Important: Clutch failure due to installation of an engine power upgrade is not covered under the manufacturers warranty. Inspect for the presence of an add-on engine power package. When engine horsepower or torque is increased over factory rating, a shift flare condition may occur.
 

Trouble Code: P2727



Pressure Control Solenoid 1 (PCS1) Control Circuit Open (A)

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P2728



Clutch Pressure Control (PC) Solenoid 5 System Performance

Possible Causes:



When attempting to set solenoid electrical DTCs, ensure the TCM is warmed up and the transmission is operated in second gear long enough to ensure a 3°C (5°F) increase in TCM substrate temperature. This will place the TCM under the optimal conditions to test solenoid electrical DTCs.
 

Trouble Code: P2729



Pressure Control Solenoid 1 (PCS1) Control Circuit Low (A)

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P2730



Pressure Control Solenoid 1 (PCS1) Control Circuit High (A)

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P2761



Torque Converter Clutch (TCC) Pressure Control (PC) Solenoid Control Circuit

Trouble Code: P2762



Torque Converter Clutch (TCC) Pressure Control Solenoid System Performance

Possible Causes:



When attempting to set solenoid electrical DTCs, ensure the TCM is warmed up and the transmission is operated in 2nd gear long enough to ensure a 3°C (5°F) increase in TCM substrate temperature. This will place the TCM under the optimal conditions to test solenoid electrical DTCs.
 

Trouble Code: P2763



Torque Converter Clutch (TCC) Pressure Control Solenoid (PCS) Control Circuit High

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P2764



Torque Converter Clutch (TCC) Pressure Control Solenoid (PCS) Control Circuit Low

Possible Causes:



Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:

A bent terminal
 
A backed-out terminal
 
A damaged terminal
 
Poor terminal tension
 
A chafed wire
 
A broken wire inside the insulation
 

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.You may have to drive the vehicle in order to experience a condition.
 

Trouble Code: P2771



Four Wheel Drive (4WD) Low Switch Circuit

Trouble Code: P2771



Four Wheel Drive (4WD) Low Switch Circuit

Possible Causes:



Verify that the input speed sensor (ISS) and the output speed sensor (OSS) are functioning properly.
 
In 3rd gear at approximately 64 km/h (40 mph), command TCC ON. If functioning properly the OSS will track ISS and the engine RPM.
 
If not, refer to DTC P0716 for the ISS and DTC P0723 for the OSS.
 

Trouble Code: P2796



Auxiliary Transmission Fluid Pump Relay Control Circuit

Possible Causes:



The Auxiliary Transmission Fluid Pump Relay can be controlled using a Scan Tool. This feature is located in the HCM Output Controls on the scan tool.
 
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P2797



Auxiliary Transmission Fluid Pump Performance

Possible Causes:



The Auxiliary Transmission Fluid Pump Relay can be controlled using a Scan Tool. This feature is located in the HPCM Output Controls on the scan tool.
 
Inspect for restricted Auxiliary Transmission Fluid Pump pickup filter.
 
Inspect for leaking at the Auxiliary Transmission Fluid Pump mounting surface.
 
Inspect charging system and battery voltage for correct operation.
 
Ensure all Engine Idle Off enabling criteria have been met to ensure auxiliary transmission fluid pump operation is possible.
 
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P2A01



HO2S Performance Bank 1 Sensor 2

Trouble Code: P2A04



HO2S Performance Bank 2 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 Speed GMLAN Device .
 
An intermittent condition is likely to be caused by a short on the GMLAN serial data circuits. Use the DMM MIN/MAX function to capture/locate intermittent conditions.
 

Trouble Code: U0073



High Speed CAN Communication Bus

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.
 

Trouble Code: U0100



Lost Communication With Engine Control Module (ECM)

Possible Causes:

The following conditions may cause the DTC to set:



A poor connection or terminal tension at a GMLAN module
 
An intermittent open on either high speed GMLAN serial data circuit
 
An open voltage or ground circuit to a module
 
An internal module malfunction
 
A short between the GMLAN serial data circuits
 
A short to voltage or ground on either of the GMLAN serial data circuits
 

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: U0106



Lost Communication With Glow Plug Control Module (GPCM)

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: U0107



Lost communication with Throttle Actuator Control (TAC) Module

Possible Causes:

Important: Reprogramming the PCM may cause a communication error between the PCM and the TAC. If the PCM detects a communication error, DTC U0107 sets. Clear any DTCs from the memory that may have been set by Reprogramming.



DTC U0107 sets if the battery voltage is low. If the customer concern is slow cranking or no crank because battery voltage is low, ignore DTC U0107. Clear any DTCs from memory that may have set from the low battery voltage condition.
 
DTC U0107 sets when there is a short to B+ on the TAC module ground circuit. Inspect the fuses for the circuits that are in the TAC module harness, i.e. cruise, brake. An inspection of the fuses may lead you to the circuit that is shorted to the TAC module ground circuit.
 
DTC U0107 sets if the TAC module ignition feed circuit is shorted to a B+ supply circuit. The TAC module stays powered-up when the ignition switch is turned OFF. When the ignition switch is turned ON, the TAC module is powered-up before the PCM. DTC U0107 sets because no communication is detected by the TAC module from the PCM. Inspect related circuits for being shorted to a B+ supply circuit.
 
Inspect the TAC module power and ground circuits and the TAC module/PCM serial data circuits for intermittent connections.
 
Inspect the TAC module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
 
When the TAC module detects a problem within the TAC system, more than one TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing an individual condition may correct more than one DTC. Remember this if you review the stored information in Capture Info.
 
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: U0111



Lost Communication With Energy Storage Control Module (ESCM)

Possible Causes:

The following conditions may cause the DTC to set:



A poor connection or terminal tension at a GMLAN module
 
An intermittent open on either high speed GMLAN serial data circuit
 
An open voltage or ground circuit to a module
 
An internal module malfunction
 
A short between the GMLAN serial data circuits
 
A short to voltage or ground on either of the GMLAN serial data circuits
 

Trouble Code: U0120



Lost Communication With Starter/Generator Control Module (SGCM)

Possible Causes:

The following conditions may cause the DTC to set:



A poor connection or terminal tension at a GMLAN module
 
An intermittent open on either high speed GMLAN serial data circuit
 
An open voltage or ground circuit to a module
 
An internal module malfunction
 
A short between the GMLAN serial data circuits
 
A short to voltage or ground on either of the GMLAN serial data circuits
 

Trouble Code: U0131



Lost Communication With Electro-Hydraulic Power Steering (EHPS) Module

Possible Causes:

The following conditions may cause the DTC to set:



A poor connection or terminal tension at a GMLAN module
 
An intermittent open on either high speed GMLAN serial data circuit
 
An open voltage or ground circuit to a module
 
An internal module malfunction
 
A short between the GMLAN serial data circuits
 
A short to voltage or ground on either of the GMLAN serial data circuits
 

Trouble Code: U0293



Lost Communication With Hybrid Control Module (HCM)

Possible Causes:

The following conditions may cause the DTC to set:



A poor connection or terminal tension at a GMLAN module
 
An intermittent open on either high speed GMLAN serial data circuit
 
An open voltage or ground circuit to a module
 
An internal module malfunction
 
A short between the GMLAN serial data circuits
 
A short to voltage or ground on either of the GMLAN serial data circuits
 

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:

The following conditions may cause the DTC to set:



A poor connection or terminal tension at a GMLAN module
 
An intermittent open on either high speed GMLAN serial data circuit
 
An open voltage or ground circuit to a module
 
An internal module malfunction
 
A short between the GMLAN serial data circuits
 
A short to voltage or ground on either of the GMLAN serial data circuits
 

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.
 

 
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