Hummer H3. Manual — part 1191

DTC B2483 or B2484

Step

Action

Values

Yes

No

Schematic Reference: OnStar Schematics
Connector End View Reference: Entertainment/Communication Connector End
Views

1

Did you perform the Diagnostic
System Check - Vehicle?

-

Go to Step 2

Go to
Diagnostic
System
Check -
Vehicle

2

1. Disconnect the navigation

antenna coax connector from the
navigation antenna.

2. Disconnect the navigation

antenna from the vehicle
communication interface module
(VCIM).

3. Measure the resistance from the

center conductor of the coax to
the metal outer shield.

Does the meter read out of limits?

NOTE:

Using a DMM to measure the resistance
of the navigation antenna coax from the
center conductor to the outer shield
while the antenna is still connected will
damage the navigation antenna.

IMPORTANT:

Vehicle may be equipped with sectioned
coax. Test each section and replace only
the faulty section, not the entire length of
coax.

-

Go to Step 3 Go to Step 4

3

Measure the resistance of the
navigation antenna coax center
conductor from end to end.
Does the resistance measure greater
than the specified value?

1 ohms

Go to Step 4 Go to Step 5

2007 Hummer H3

2007 ACCESSORIES AND EQUIPMENT Cellular, Entertainment and Navigation - H3

DTC U1500

Circuit Description

4

Replace the navigation antenna coax.
Did you complete the replacement?

-

Go to Step 7

-

5

Inspect for poor connections at the
navigation antenna and the harness
connector of the VCIM. Refer to
Testing for Intermittent
Conditions and Poor Connections
and Connector Repairs .
Did you find and correct the
condition?

-

Go to Step 7 Go to Step 6

6

Replace the navigation antenna. Refer
to Cellular
Communications/Digital Radio
Antenna Replacement.
Is the repair complete?

-

Go to Step 7

-

7

1. Use the scan tool in order to

clear the DTCs.

2. Operate the vehicle within the

Conditions for Running the DTC
as specified in the supporting
text.

Does the DTC reset?

-

Go to Step 8 System OK

8

Replace the VCIM. Refer to Control
Module References for replacement,
setup and programming.
Did you complete the replacement?

-

Go to Step 9

-

9

1. Use the scan tool in order to

clear the DTCs.

2. Operate the vehicle within the

Conditions for Running the DTC
as specified in the supporting
text.

Does the DTC reset?

-

Go to Step 2

-

2007 Hummer H3

2007 ACCESSORIES AND EQUIPMENT Cellular, Entertainment and Navigation - H3

This DTC indicates an internal fault and is set within the vehicle communication interface module
(VCIM). No external circuits are involved.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC U1500 Inter-Device Dedicated Bus Malfunction

Conditions for Running the DTC

The microprocessor runs the program to detect an internal fault during module power up and
every 10 seconds thereafter until the module re-enters the sleep mode.

Conditions for Setting the DTC

The VCIM detects an internal communication malfunction.

Action Taken When DTC Sets

The OnStar® status LED turns RED.

The vehicle is unable to connect to the OnStar® Call Center.

Conditions for Clearing the DTC

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

A history DTC clears after 50 malfunction-free ignition cycles.

Diagnostic Aids

The diagnostic procedure used for DTC U1500 in OnStar® systems with single module
generations of OnStar® differ greatly from previous generations with 2 modules. While
these older generations denoted a failure of the 3-wire bus between the modules by setting a
U1500, single module OnStar® systems use this DTC to denote an internal module failure.
The determination of whether a one or 2-module generation of OnStar® is used should be
confirmed. Refer to

OnStar Description and Operation

.

This DTC may be stored as a history DTC without affecting the operation of the module. If
stored only as a history DTC and not retrieved as a current DTC, do not replace the VCIM.

If this DTC is retrieved as both a current and history DTC, replace the VCIM.

DTC U1500

Step

Action

Yes

No

2007 Hummer H3

2007 ACCESSORIES AND EQUIPMENT Cellular, Entertainment and Navigation - H3

SYMPTOMS - CELLULAR COMMUNICATION

1. Perform the Diagnostic System Check - Vehicle . Before using the Symptom Tables,

verify that all of the following are true:

There are no DTCs set.

The control module can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions.

Refer to OnStar Description and Operation.

3. Perform the OnStar Symptom Diagnosis. This symptom table will enable the user to

verify the customer complaint and narrow it to its source.

1

Did you perform the Diagnostic System
Check - Vehicle?

Go to Step 2

Go to
Diagnostic
System Check -
Vehicle

2

1. Install a scan tool.

2. Turn ON the ignition, with the

engine OFF.

3. Retrieve DTCs from the vehicle

communication interface module
(VCIM).

Is the DTC retrieved as a current DTC?

Go to Step 3

Go to Diagnostic

Aids

3

Replace the VCIM. Refer to Control
Module References for replacement,
setup and programming.
Did you complete the replacement?

Go to Step 4

-

4

1. Use the scan tool in order to clear

the DTCs.

2. Operate the vehicle within the

Conditions for Running the DTC as
specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK

IMPORTANT: The following steps must be completed before using the symptom

tables.

2007 Hummer H3

2007 ACCESSORIES AND EQUIPMENT Cellular, Entertainment and Navigation - H3