Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2008AVALANCHE 1500 2WD V8-6.0LREPAIR AND DIAGNOSISA L L DIAGNOSTIC TROUBLE CODES ( DTC )TESTING AND INSPECTIONP CODE CHARTSP1762
2008 Chevrolet Avalanche 1500 2WD V8-6.0L
P1762
2008 Chevrolet Avalanche 1500 2WD V8-6.0LSECTION P1762
DTC P1762
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P01762
- Transmission Mode Switch Signal Circuit
Circuit/System Description
The Transmission Mode Switch Signal enables the operator to achieve enhanced shift performance when towing or hauling a load. When tow/haul mode is selected, the tow/haul switch input signal to the body control module (BCM) is momentarily toggled to zero volts. This code sets when the rolling count of the transmission control module (TCM) does not match the same value sent from the BCM.
Conditions for Running the DTC
The engine run time is greater than 5 seconds.
Conditions for Setting the DTC
The TCM detects an error in the rolling count value that does not match with the BCM.
Action Taken When the DTC Sets
* DTC P1762 is a Type C DTC.
* The TCM forces normal shift operation.
Conditions for Clearing the DTC
DTC P1762 is a Type C DTC.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views
Description and Operation
Transmission General Information (Transmission General Information)
Electrical Information Reference
* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Transmission Control Module Scan Tool Information (4L60-E) Transmission Control Module Scan Tool Information (6L50/6L80/6L90)
Circuit/System Testing
Ignition ON, attempt to establish communication with the BCM with a scan tool.
If no communication with the BCM, refer to Control Module References for further diagnosis.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Refer to Control Module References for TCM replacement, setup and reprogramming.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.