AutoCodes - Buick - U1026 BUICK

U1026 BUICK Code - Invalid Or Missing Data For Transfer Case Shift Control Module

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3
Table of contents

|U1026 BUICK code possible causes

  • Faulty Transfer Case Shift Control Module (TCSCM)
  • Transfer Case Shift Control Module harness is open or shorted
  • Transfer Case Shift Control Module circuit poor electrical connection

|How do I fix the U1026 BUICK code?

Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

|U1026 BUICK code tech notes

This is typically an electrical wiring connection issue at one of the controllers being monitored by the manufacturer.
It can occur if:
Someone changes a battery while the ignition switch is left on, that is, left in the “Run” position.
Someone flashes/upgrades their engine controller – other modules unable to communicate with PCM during this process – this will set U1026 at a multitude of controllers on the vehicle – all false codes. Erase and carry on.
May need to disconnect both battery cables and touch them together for 15 seconds. Reattach battery cables, positive first, then negative and see if a soft reset helps.

|Cost of diagnosing the U1026 BUICK code

Labor: 1.0

The cost of diagnosing the U1026 BUICK code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

|What are U1026 BUICK code possible symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Service 4WD Light ON
  • Engine cranks but may not start – may be intermittent
  • May / may not shift from 2-wheel drive to 4-wheel drive / 4-wheel drive to 2-wheel drive
  • May or may not be able to communicate with a scan tool / depends on problem

|U1026 BUICK code description

Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for the state of health monitoring/node alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that module node alive message. Each module on the class 2 serial data circuit is required to send a Node Alive message every 2 seconds. When no message is detected from a learned identification number for 5 seconds, a Diagnostic Trouble Code (DTC) U1026 is set.
OBDII Code U1026 Buick - Invalid Or Missing Data For Transfer Case Shift Control Module -

|Need more information with the U1026 BUICK code?

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|Need help with a U1026 BUICK code?

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|U1026 BUICK code comments

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