Avalanche, Express, Savana 2006-2007

8.1L V8 VIN G Auto 5

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Trouble Code: P1154



HO2S Transition Time Ratio Bank 2 Sensor 1

Trouble Code: P1380



Misfire Detected - Rough Road Data Not Available

Trouble Code: P1381



Misfire Detected - No Communication with Brake Control Module

Trouble Code: P1516



Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance

Possible Causes:



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.
 
Verify that the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.
 
When the TAC module detects a condition 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. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
 
For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P1574



Stoplamp Switch Circuit

Possible Causes:



Refer to Exterior Lighting Systems Description and Operation in order to avoid a misdiagnosis.
 
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P1600



Control Module Long Term Memory Performance

Trouble Code: P1621



Control Module Long Term Memory Performance

Trouble Code: P1626



Theft Deterrent Fuel Enable Signal Lost

Possible Causes:

Important: Do not clear DTCs unless directed by a diagnostic procedure. Clearing DTCs will also clear valuable Freeze Frame and Failure Records data.



Inspect for published service bulletins relating to exhibited symptoms or component operation.
 
Inspect all related wiring and connections including the PCM and BCM connections. These may cause an intermittent malfunction.
 
If the class 2 serial data circuit is shorted to ground or shorted to voltage, then all systems connected to the serial data circuit will not be able to communicate properly. Systems capable of storing loss of communications DTCs, or the DTCs with the letter "U" as a prefix, will have these codes stored in their memory. If a DTC U1192 is stored in the PCM memory along with the P1626, then a fault occurred at some point after the PCM received the correct password. The BCM must also be inspected for intermittent operation due to a loss of power or ground to the module itself. After repairing the cause of DTC 1626, clear all DTCs from the systems capable of storing this DTC and DTC U1192.
 
The VTD Passlock parameters can be monitored in the PCM under engine data 2, display with a scan tool.
 
The scan tool Diagnostic Circuit Check can be used to:

Monitor the class 2 serial data circuit for modules which have been or are communicating.
 
Monitor for loss of communications DTCs with the letter "U" as a prefix: U1001-U1199.
 
Clear loss of communication DTCs. When a Clear Codes command is issued, all codes, Freeze Frame and Failure Records information is cleared.
 

The scan tool Class 2 Message Monitor will show the status of each module on the class 2 circuit. A status of Active indicates that the module is communicating with the scan tool. An Inactive status indicates that the module previously communicated with the scan tool, but is not communicating currently. The inactive status will only appear if the loss of communication occurs while on the Message Monitor screen. If a module is not listed at all, then the missing module never successfully established communications with the scan tool or lost communication while on another screen. Refer to Scan Tool Does Not Communicate with Class 2 Device in Computer/Integrating Systems for the complete class 2 data link to determine if there are any unlisted modules.An intermittent may be caused by any of the following conditions:

A poor connection
 
Rubbed through wire insulation
 
A broken wire inside the insulation
 

Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
 

Trouble Code: P1627



Control Module Long Term Memory Performance

Trouble Code: P1630



Theft Deterrent Learn Mode Active

Trouble Code: P1631



Theft Deterrent Fuel Enable Signal Not Correct

Possible Causes:

Important: Do not clear DTCs unless directed by a diagnostic procedure. Clearing DTCs will also clear valuable Freeze Frame and Failure Records data.



If the PCM is replaced, the PCM must re-learn a valid password and crankshaft variation.
 
If the BCM is replaced, the PCM must re-learn a valid password.
 
Check for published service bulletins relating to exhibited symptoms or component operation.
 
If the vehicle does not start, or starts and stalls:

Turn OFF the ignition and wait at least 5 seconds before trying to restart.
 
If a fault or tamper has been detected, the BCM will not forward the correct password to the PCM for a period of 10 minutes, even if the condition is corrected during that time period. This may cause a DTC P1631 to set in the PCM. This timer can be monitored in the Passlock Data parameter of the scan tool. Once the time has elapsed, the BCM will determine if the condition is still present.
 

The PCM and BCM parameters can be monitored with a scan tool.The Passlock state and the auto learn timer can be viewed in the Passlock Data parameter of the scan tool.Inspect the following for preventing the Passlock sensor from communicating with the BCM:

Passlock sensor
 
Ignition switch assembly
 
Passlock sensor circuitry
 
Bent pins at the small Passlock sensor
 

If this DTC sets along with a DTC B2960, then the problem was caused by malfunctioning Passlock components or circuitry, not the PCM.Inspect all related wiring and connections including the PCM and BCM connections. These may cause an intermittent malfunction.An intermittent may be caused by any of the following conditions:

A poor connection
 
Rubbed through wire insulation
 
A broken wire inside the insulation
 

Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
 

Trouble Code: P1644



Traction Control Delivered Torque Output Circuit

Possible Causes:

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:



Testing for Electrical Intermittents
 
Testing for Intermittent Conditions and Poor Connections
 
Wiring Repairs
 
Connector Repairs
 

Trouble Code: P1680



Powertrain Control Module Internal Malfunction

Trouble Code: P1681



Powertrain Control Module Internal Malfunction

Trouble Code: P1683



Powertrain Control Module Internal Malfunction

Trouble Code: P1689



Traction Control Delivered Torque Output Circuit

Possible Causes:

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:



Testing for Electrical Intermittents
 
Testing for Intermittent Conditions and Poor Connections
 
Wiring Repairs
 
Connector Repairs
 

Trouble Code: P1810



Transmission Fluid Pressure (TFP) Position Switch Circuit

Possible Causes:



Refer to the Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic table for the normal range signals and the invalid combinations. On the table, LOW is 0 volts, HI is ignition voltage.
 
Sediment in the valve body may cause improper operation of the TFP manual valve position switch. If sediment intrusion is suspected, clean the valve body and replace the TFP manual valve position switch.
 

Trouble Code: P1810



Transmission Fluid Pressure (TFP) Position Switch Circuit

Possible Causes:



Refer to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic for the normal range signals and the illegal or invalid switch combinations.
 
DTC P1810 can set from low pump pressure, a stuck pressure regulator, or unit refill from overhaul and pan removal.
 
DTC P1810 can be set by a slipping forward clutch, allowing a 2.08:1 ratio, reverse, when the manual valve position is indicated as D4.
 
DTC P1810 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 

Trouble Code: P2066



Fuel Level Sensor 2 Performance

Possible Causes:



Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the vehicle within the same Freeze Frame conditions, including those for RPM, for engine load, for vehicle speed, for temperature, and for others. This will isolate when the DTC failed. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
 

Trouble Code: P2067



Fuel Level Sensor 2 Circuit Low Voltage

Possible Causes:



Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the vehicle within the same freeze frame conditions, including those for RPM, for engine load, for vehicle speed, for temperature, and for others. This will isolate when the DTC failed. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
 

Trouble Code: P2068



Fuel Level Sensor 2 Circuit High Voltage

Possible Causes:



Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the vehicle within the same freeze frame conditions, including those for RPM, for engine load, for vehicle speed, for temperature, and for others. This will isolate when the DTC failed. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
 

Trouble Code: P2101



Control Module Throttle Actuator Position Performance

Possible Causes:



Inspect for mechanical concerns or binding that may be temperature related. Components may not move freely in extreme heat or cold due to the presence of contaminants or ice formation.
 
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 condition 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. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
 
For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P2108



Throttle Actuator Control (TAC) Module Performance

Possible Causes:



Verify that the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.
 
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 condition within the TAC System, more than 1 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 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
 

Trouble Code: P2120



Accelerator Pedal Position (APP) Sensor 1 Circuit

Possible Causes:



Inspect the throttle actuator control (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 condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
 
For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P2121



Accelerator Pedal Position (APP) Sensor 1 Performance

Possible Causes:



Inspect the throttle actuator control (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 condition 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 one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
 
For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P2125



Accelerator Pedal Position (APP) Sensor 2 Circuit

Possible Causes:



Inspect the throttle actuator control (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 condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
 
For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P2135



Throttle Position (TP) Sensor 1-2 Correlation

Possible Causes:



Inspect the throttle actuator control (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 condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
 
If this DTC is determined to be intermittent, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P2138



Accelerator Pedal Position (APP) Sensor 1-2 Correlation

Possible Causes:



The PCM compares the signal of each of the accelerator pedal position sensor to each other throughout the entire range of operation. Clear the DTCs and actuate the pedal through the entire range with the ignition ON and the engine OFF.
 
Use the J 35616 Connector Test Adapter Kit for any test that requires probing the PCM harness connector or a component harness connector. Using this kit will prevent damage to the harness connector terminals.
 
For intermittent conditions, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P2610



Control module Ignition Off Timer Performance

Trouble Code: P2636



Fuel Transfer Pump Flow Insufficient

Trouble Code: P2761



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

Possible Causes:



DTC P2761 defaults to an elevated line pressure condition which may result in partial TCC apply. This may produce an idle surge that could stall the engine.
 

Trouble Code: P2761



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

Trouble Code: P2771



Four Wheel Drive (4WD) Low Switch Circuit

Trouble Code: P2771



Four Wheel Drive (4WD) Low Switch Circuit

Possible Causes:



Low pump pressure and a slipping transmission may cause DTC P2771 to set.
 
Transfer case ratio is calculated by dividing the ISS by 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 Circuit Bank 1 Sensor 2

Trouble Code: P2A04



HO2S Circuit 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.
 

 
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