GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Chevy Suburban - 2WD 🢒 Engine 🢒 Engine Controls - 6.5L 🢒 DTC U1026 Loss of ATC Class 2 Communication

Object Number: 192130 Size: MF
Engine Controls Components
PWR, GND, and DLC
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The PCM monitors the serial data (class II) circuit for communications from the Automatic Transfer Case (ATC) controller. If the ATC controller is not communicating with the PCM this DTC will set.

Conditions for Setting the DTC

No serial data (class II) from ATC controller to the PCM.

Action Taken When the DTC Sets

This DTC will not illuminate the MIL.

Conditions for Clearing the MIL/DTC
    • A History DTC will clear after 40 consecutive warm up cycles with no failures of any non-emissions related diagnostic test.
    • PCM battery voltage is interrupted.
    • Use of a scan tool.

Diagnostic Aids

This DTC will not set unless the PCM and ATC controllers have already establish communications first.. This DTC will only diagnosis an open or intermittent connection from the ATC controller to the splice.

Test Description

The number(s) below refer to the step number(s) on the Diagnostic Table.

  1. In this step, the Powertrain OBD System Check is being performed.

Step

Action

Value(s)

Yes

No

1

Important:: Before clearing DTCs, use the Scan Tool Capture Info to record Freeze Frame and Failure Records for reference, as data will be lost when Clear Info function is used.

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

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Go to ATC Controller Diagnosis

Go to Powertrain On Board Diagnostic (OBD) System Check