Entertainment System: Overview GMC Savana H2500

Test Description

The numbers below Refer to the step numbers on the diagnostic table.

1. 2. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
2. 3. The symptom list in Symptoms will determine the correct diagnostic procedure to use.
3. 4. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

Scheme 1

Scheme 2

Scheme 3

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

1. 3. This step isolates the fault condition.

Scheme 4

Symptoms - Entertainment

Important: The following steps must be completed before using the symptom tables.

1. Perform the «Diagnostic System Check - Radio/Audio System»(ref-176307-S30284169342005050300000) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control module(s) can communicate via the serial data link.
2. Review the «Radio/Audio System Description and Operation»(ref-176307-S22286911612005050300000) in order to familiarize yourself with the system functions.

Radio/Audio System Description and Operation

The Entertainment System on this vehicle is configured with either a base or an uplevel system. Both the base and uplevel systems contain a radio, antenna, and speakers.

The uplevel system differs from the base level system by providing the customer with enhanced audio system features. Some of those features may include the radio data system (RDS), extended range speakers, and a remote playback device.

The following list shows the base and uplevel radios available for this vehicle

Scheme 5

Scheme 6

Scheme 7

1. Base Radio (UM7 RPO Code) - AM/FM
2. Base Radio (U1C RPO Code) - AM/FM with CD
3. Uplevel Radio (UB1 RPO Code) - AM/FM, Cassette and CD
4. Uplevel Radio (UC6 RPO Code) - AM/FM, Integral Multi Disc CD Changer

Each item in the list below represents topics covered in detail below

1. AM/FM Reception
2. Antenna
3. Audio Amplifier
4. Theft Deterrent
5. Integral Multi Disc CD Changer (IMDX)
6. Remote Playback Device
7. Radio Data System (RDS)
8. Radio Error Messages

Service Programming System (SPS) Description

The service programming system (SPS) allows a technician to program a control module through the data link connector (DLC). The information transfer circuit that is used at the DLC is the same serial data circuit used by the scan tool for retrieving diagnostic trouble codes (DTCs), displaying data, clearing DTCs, etc. This procedure offers the ability to install software/calibrations matched to a particular vehicle.

Most control modules have 2 types of memory.

The software/calibrations reside in the flash memory.

The 2 types of memory are listed below

1. Electrically Erasable Programmable Read Only Memory (EEPROM) This type of memory allows selected portions of memory to be programmed while other portions remain unchanged. Certain learned values reside in the EEPROM, such as: The vehicle identification number (VIN) The crankshaft variation learned position The software/calibrations identification numbers The control module security information
2. Flash Read Only Memory - Flash Memory Flash memory has increased memory storage capacity. During programming all information within this type of memory is erased, and then replaced with entirely new information.