DTC U1881-U1899. GMC Truck GMC K Sierra

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2004 🢒 GMC K Sierra - 4WD 🢒 DTC 🢒 DTC U1881-U1899

Circuit Description

Modules connected to the class 2 and high speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. All DTCs in this range are reported on class 2 link to the scan tool by powertrain control module (PCM) even if they may be set by different modules.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

•	DTC U1881 Electro-Hydraulic Power Steering (EHPS) Module Lost Communication With Energy Storage Control Module (ESCM)

•	DTC U1882 Energy Storage Control Module (ESCM) Lost Communication With Electro-Hydraulic Power Steering (EHPS) Module

•	DTC U1883 Hybrid Control Module (HCM) Lost Communication With Driver Door Module (DDM)

•	DTC U1884 Hybrid Control Module (HCM) Lost Communication With Passenger Door Module (PDM)

•	DTC U1885 Energy Storage Control Module (ESCM) Lost Communication With Hybrid Control Module (HCM)

•	DTC U1886 Energy Storage Control Module (ESCM) Lost Communication With Powertrain Control Module (PCM)

•	DTC U1887 Energy Storage Control Module (ESCM) Lost Communication With Starter/Generator Control Module (SGCM)

•	DTC U1888 Hybrid Control Module (HCM) Lost Communication With Energy Storage Control Module (ESCM)

•	DTC U1889 Hybrid Control Module (HCM) Lost Communication With Body Control Module (BCM)

•	DTC U1890 Hybrid Control Module (HCM) Lost Communication With HVAC Control Module

•	DTC U1891 Hybrid Control Module (HCM) Lost Communication With Instrument Panel Cluster (IPC)

•	DTC U1892 Hybrid Control Module (HCM) Lost Communication With Electro-Hydraulic Power Steering (EHPS) Module

•	DTC U1893 Hybrid Control Module (HCM) Lost Communication With Powertrain Control Module (PCM)

•	DTC U1894 Hybrid Control Module (HCM) Lost Communication With Starter/Generator Control Module (SGCM)

•	DTC U1895 Electro-Hydraulic Power Steering (EHPS) Module Lost Communication With Powertrain Control Module (PCM)

•	DTC U1896 Electro-Hydraulic Power Steering (EHPS) Module Lost Communication With Starter/Generator Control Module (SGCM)

•	DTC U1897 Starter/Generator Control Module (SGCM) Lost Communication With Energy Storage Control Module (ESCM)

•	DTC U1898 Starter/Generator Control Module (SGCM) Lost Communication With Hybrid Control Module (HCM)

•	DTC U1899 Starter/Generator Control Module (SGCM) Lost Communication With Powertrain Control Module (PCM)

Conditions for Running the DTC

Voltage supplied to the module is in the normal operating voltage range of 9-16 volts.

Conditions for Setting the DTC

A node alive message has not been received from an identified module within the last 5 seconds after establishing class 2 serial data communication, or a supervised high speed GMLAN message has not been received.

Action Taken When the DTC Sets

The module uses a default value for the missing parameter.

Conditions for Clearing the DTC

•	A current DTC clears when the malfunction is no longer present.

•	A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Diagnostic Aids

Important:

•	For DTC U1892, ensure all power and ground circuits to the electric-hydraulic power steering (EHPS) module including the motor are tested. A loss of voltage or ground to the EHPS hydraulic motor as well as to the module may cause a loss of communication.

•	DTCs U1883 and U1884 can be set inadvertently, when braking during the trailer towing. If the codes are set as history only, clear the codes.

•	An intermittent open between a module and a star connector may cause this DTC to set.

•	An intermittent open on high speed GMLAN may cause this DTC to set.

•	An open voltage or ground circuit to a module may cause this DTC to set.

•	An internal module malfunction may cause this DTC to set.

Test Description

The number below refers to the step number on the diagnostic table.

The module which was not communicating may have set Loss of Communication DTCs for those modules that it was monitoring.

Step

Action

Yes

Schematic Reference: Data Link Connector Schematics

Connector End View Reference: Master Electrical Component List and Inline Harness Connector End Views in Wiring Systems

Was any DTC in the range U1001-U1254 recorded?

Go to DTC U1001-U1254

Go to Step 2

Was any DTC in the range U0100-U0299 recorded?

Go to DTC U0100-U0299

Go to Step 3

Important:

•	Use the DTC Descriptors list in order to determine which module is not communicating.

•	If multiple DTCs were set, consider the closest module to the powertrain control module (PCM) as the non-communicating module.

•	A loss of voltage to the electric-hydraulic power steering (EHPS) hydraulic motor as well as to the module may cause a loss of communication.

Test the following circuits of the module that is not communicating for an open or a short to ground:

•	The battery positive voltage input circuits

•	The battery positive voltage output circuits

•	The ignition voltage input circuits

•	The ignition voltage output circuits

•	The switched battery positive voltage circuits

Refer to the following:

•	Control Module References in Body Control System for the applicable schematic

•	Circuit Testing in Wiring Systems

•	Wiring Repairs in Wiring Systems

Did you find and correct the condition?

Go to Step 8

Go to Step 4

Important: A loss of ground to the EHPS hydraulic motor as well as to the module may cause a loss of communication.

Turn OFF the ignition.
Test the ground circuits of the module that is not communicating for an open.

Refer to the following:

•	Control Module References in Body Control System for the applicable Schematic

•	Circuit Testing in Wiring Systems

•	Wiring Repairs in Wiring Systems

Did you find and correct the condition?

Go to Step 8

Go to Step 5

Test the class 2 or/and high speed GMLAN serial data circuits of the module that is not communicating for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 6

Inspect the harness connectors of the module that is not communicating for poor connections and terminal tension at the following circuits:

•	The battery positive voltage input circuits

•	The battery positive voltage output circuits

•	The ignition voltage input circuits

•	The ignition voltage output circuits

•	The switched battery positive voltage supply circuits

•	The ground circuits

•	The class 2 or/and high speed GMLAN serial data circuits

Refer to the following:

•	Control Module References in Body Control System for the applicable schematic

•	Testing for Intermittent Conditions and Poor Connections in Wiring Systems

•	Connector Repairs in Wiring Systems

Did you find and correct the condition?

Go to Step 8

Go to Step 7

Important: Perform the programming or set up procedure for the module, if required.

Replace the module that is not communicating. Refer to Control Module References for the applicable replacement procedure.

Did you complete the replacement?

Go to Step 8

Install a scan tool.
Turn ON the ignition with the engine OFF.
Select the Display DTCs function for the module which was not communicating.

Does the scan tool display any DTCs which do not begin with a "U"?

Go to Control Module References for the applicable Diagnostic System Check

Go to Step 9

Select the Display DTCs function for the modules which had the Loss of Communications DTC set.

Does the scan tool display any DTCs which do not begin with a "U"?

Go to Control Module References for the applicable Diagnostic System Check

Go to Step 10

Use the scan tool in order to clear the DTCs.
Continue diagnosing or clearing the DTCs until all the modules have been diagnosed and all the DTCs have been cleared.

Did you complete the action?

Go to Control Module References for the applicable Diagnostic System Check