Begin the system diagnosis with the DIAGNOSTIC SYSTEM CHECK - NAVIGATION SYSTEM .
The Diagnostic System Check will provide the following information
- The identification of the control module(s) which command the system
- The ability of the control module(s) to communicate through the serial data circuit
- The identification of any stored diagnostic trouble codes (DTCs) and their status
The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.
The numbers below refer to the step numbers on the diagnostic table.
- 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.
- 3. Checks for DTCs for each module of the system.
- 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.
8-Digit GM Part Number : The scan tool displays an 8 digit numeric number. The part number of the module.
Amplifier : The scan tool displays Present or Not Present. The scan tool displays Present when the amp sense wire has been grounded to signal that an amplifier is present.
Amp Type : The scan tool displays Bose/Non-Bose, the type of amplifier installed in the vehicle.
Antenna Enable : The scan tool displays Active/Inactive.
Band Number : The scan tool displays AM/FM1/FM2. The current band that the radio is in.
Calibration ID : The scan tool displays 0-9999. The number designating what calibrations the module contains.
CD Changer : The scan tool displays Connected/Not Connected. The scan tool displays Connected when the radio receives Class 2 information from the CD changer.
Channel Number : The scan tool displays the channel the radio is tuned to.
Driver Number : The scan tool displays Driver 1-2. The memory position the driver has selected as received by Class 2 lines.
Fan Control : The scan tool displays the status of the fan.
Julian Date of Build : The scan tool displays 0-999. The day of the year that the module was built.
New VIN Counter : The scan tool displays 0-99. The number of times a new VIN number has been set in the radio.
Phone : The scan tool displays Present or Not Present. The scan tool displays Connected when the radio receives Class 2 information from the phone module.
Power Mode Config. : The scan tool displays the current power mode of the vehicle.
Preset Control : The scan tool displays Preset 1-6 when the radio is on a preset station, or Not A Preset when the radio is not on a preset station.
PROM ID : The scan tool displays 0-9999. The identification number of the modules internal PROM.
Signal Strength : The scan tool displays the strength of the received signal in dB.
Theft Armed : The scan tool displays Learned VIN/No VIN. The Scan tool displays Learned VIN when the theft mode has been turned ON by recognizing a valid VIN.
Theft Lock : The scan tool displays Locked/Unlocked. The scan tool displays Unlocked when the radio receives the correct VIN information from the PCM via Class 2.
Year Module Built : The scan tool displays a 1990-2020, the production year the module was manufactured.
The navigation radio receives the vehicle speed signal from the PCM through a dedicated circuit shared with the instrument cluster.
- The navigation radio must detect a power mode transition to ON.
- The radio does not set this DTC if B1327 or B1328 is current.
- The vehicle must drive for 4 km (2.5 mi) after receiving a GPS signal. The receipt of the GPS signal is indicated by an icon box in the upper left quadrant of the map screen with the letters GPS inside of it.
The navigation radio compares the vehicle speed signal from the PCM to the GPS location signal every second. If the GPS signal indicates that the vehicle has traveled 4 km (2.5 mi) but no vehicle speed signal was received, the radio sets the DTC.
The navigation radio uses the GPS signal when the vehicle speed signal from the PCM is unavailable.
The following symptoms may happen if the vehicle speed signal from the PCM is unavailable
- The vehicle icon may jump to different positions on the map screen.
- The vehicle icon, current position marker may not move on the map screen while the vehicle is being driven.
- The route guidance accuracy may be degraded.
- A current DTC clears when the navigation radio detects the vehicle speed signal from the PCM for more than one second.
- A history DTC clears after 50 ignition cycles without a vehicle speed signal failure.
An intermittent condition may be caused by the following
- Mis-routed harness
- Rubbed through wire insulation
- Broken wire inside the insulation
- A loose connector pin
The numbers below refer to the step numbers on the diagnostic table.
- 1. Determines if the malfunction is present.
- 3. Tests for an open in the vehicle speed signal circuit between the instrument cluster and the navigation module (NAV). A short would cause the instrument cluster to malfunction as well as the navigation system.
The global positioning system (GPS) antenna is connected to the navigation radio by a coaxial cable.
The radio must detect one of the following power modes
- ACC
- ON
- RAP
- RAP UNLK
DTC B2462 does not set if DTC B1328 or B1327 is current.
- The navigation radio test the GPS antenna every 0.3 second.
- The radio determines there is an open in the GPS antenna.
- DTC B2462 does not set if DTC B1328 or B1327 is current.
Unable to get GPS location updated, the radio uses the last reported position and the vehicle speed signal to calculate the vehicle position.
Route guidance may be inaccurate.
This failure has no effect outside the navigation system.
- A current DTC clears when the radio does not detect the failure for more than 10 seconds.
- A history DTC clears after 50 ignition cycles with no repeat of the failure.
An intermittent condition may be caused by the following
- Mis-routed harness
- Rubbed through wire insulation
- Broken wire inside the insulation
The numbers below refer to the step numbers on the diagnostic table.
- 1. Determines if the malfunction is present.
- 3. Determines if the malfunction is due to an internal fault in the navigation radio or a GPS antenna failure.
Important: The following steps must be completed before using the symptom tables.
- Perform the «DIAGNOSTIC SYSTEM CHECK - NAVIGATION SYSTEM»(/cadillac/escalade/gmt800-2001-2006/remont/navigation-system/#navigation-systems) 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.
- Review «NAVIGATION SYSTEM DESCRIPTION AND OPERATION»(/cadillac/escalade/gmt800-2001-2006/remont/navigation-system/#navigation-systems) in order to familiarize yourself with the system functions.
- Inspect for aftermarket devices which could affect the operation of the navigation system components. Refer to «CHECKING AFTERMARKET ACCESSORIES»(/cadillac/escalade/gmt800-2001-2006/remont/body-electrical/#wiring-systems-general-information__checking-aftermarket-accessories) in Wiring Systems.
- Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom
- Remove the I/P top pad. Refer to TRIM PANEL REPLACEMENT - INSTRUMENT PANEL (I/P) UPPER in Instrument Panel, Gages and Console.
- Remove the radio. Refer to RADIO REPLACEMENT in Entertainment.
- Remove the GPS antenna screw (1). Important : Observe the routing of the GPS antenna cable to ensure the GPS antenna cable is routed properly during installation.
- Remove the GPS cable from the I/P) structure.
- Remove the GPS antenna (2) from the vehicle.
- Install the GPS antenna (2) to the I/P bracket.
- Route the GPS antenna cable to the radio opening, as noted in the removal procedure. NOTE: Refer to «FASTENER NOTICE»(/cadillac/escalade/gmt800-2001-2006/remont/oem-general-information/#gm-vehicles-cautions-notices__fastener-notice) in Cautions and Notices.
- Install the screw (1). Tighten Tighten the screw (1) to 2 N.m (18 lb in).
- Install the radio. Refer to RADIO REPLACEMENT in Entertainment.
- Install the I/P top pad. Refer to TRIM PANEL REPLACEMENT - INSTRUMENT PANEL (I/P) UPPER in Instrument Panel, Gages and Console.
The navigation system contains the following components
- Navigation radio
- Global positioning system (GPS) antenna
This component acts as the operator interface for the audio system, provides the data input from the operator to the navigation system and provides navigation information to the operator via the display screen. The navigation radio, located in the center of the instrument panel, provides the following
- A display screen- All navigation and audio functions are displayed on this screen
- The navigation system map with routing information displayed on the navigation radio screen
- Audio system options and controls, displayed on the navigation radio screen
- Provides verbal guidance to the operator
- The DVD provides the map data for navigation and map route guidance
- Connection to the global positioning system (GPS) antenna, which provides the vehicle position information
The GPS antenna is located at the top center of the dash pad. The GPS antenna is powered through the same coaxial cable used to send the signals to the navigation radio. The GPS antenna collects data from the GPS satellites and routes this information to the navigation radio to be formatted into current position.
The GPS shows the current position of the vehicle. Tall buildings, large trucks, or a tunnel can obstruct GPS signals. Metallic objects on the dash can also cause interference. A GPS icon is located in the top left corner of the map display. If the GPS is valid, the icon will be green if not the icon will be gray. The GPS info screen will also show the condition of the GPS. If GPS reception in not received, it will show out of range. If the reception is received, the coordinates of your location will be shown.
The map will display the route to the selected destination. Voice prompts alert the operator of upcoming events (turns) and arrivals at the destination. The navigation system will automatically recalculate if the route is not followed. The navigation radio uses data received from the GPS satellites as well as the vehicle speed signal to accurately display the current position of the vehicle.
Points of interests are locations that are frequently visited. Points of interest can be displayed on the map or set as a destination. The following is a few of the available POI
- Gas station
- Restaurant
- Museum
- College
- Police
The map DVD is loaded in the DVD slot above the display screen. Music CDs can also be played from this slot, however, route guidance and navigation will not be available when playing a music CD. The map DVD must be in for navigation and route guidance.