Silverado 3500 2WD V8-6.0L VIN U (2004)
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The digital radio receiver (DRR)
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The driver seat module (DSM)
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The electronic brake control module (EBCM)
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The front passenger door module (FPDM)
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HVAC Control Module
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The hybrid control module (HCM), for PHT
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The instrument panel cluster (IPC)
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The powertrain control module (PCM)
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Radio
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The rear seat audio (RSA) controller
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The rear seat entertainment (RSE) assembly
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The rear wheel steering control module (RWSCM)
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The inflatable restraint sensing and diagnostic module (SDM)
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The transmission control module (TCM)
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The transfer case shift control module (TCSCM)
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The vehicle communication interface module (VCIM)
3. The following DTCs may be retrieved with a history status, but are not the cause of the present condition.
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U1300
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U1301
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U1305
6. A state of health DTC with a history status may be present along with a U1000 or U1255 code having a current status. This indicates that the
malfunction occurred when the ignition was ON.
7. Data link connector terminals 2 and 5 provide the connection to the class 2 serial data circuit and the signal ground circuit respectively.
10. A poor connection at DLC terminal of the splice pack SP205 would cause this condition but will not set a DTC.
11. An open or a short in the class 2 serial data circuit between the DLC and splice pack SP205 will prevent the scan tool from communicating with
any module. This condition will not set a DTC.
13. This test isolates the BCM class 2 serial data circuits.
16. The BCM detects that the ignition is ON and sends the appropriate power mode message to the other modules. Therefore, the BCM must remain
connected to the DLC for any other module to communicate with the scan tool. This test isolates the splice pack SP207 serial data circuits.
21. This test isolates the rest of the splice pack SP205 serial data circuits.
25. If there are no current DTCs that begin with a "U", the communication malfunction has been repaired.
26. The communication malfunction may have prevented diagnosis of the customer complaint.
Scan Tool Does Not Communicate With High Speed GMLAN Device
SCAN TOOL DOES NOT COMMUNICATE WITH HIGH SPEED GMLAN DEVICE
CIRCUIT DESCRIPTION
Modules connected to the high speed GMLAN serial data circuits monitor for serial data communications on the high speed GMLAN network during
normal vehicle operation. Operating information and commands are exchanged among the modules.
The scan tool communicates with the following modules via the high speed GMLAN:
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The energy storage control module (ESCM)
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The starter/generator control module (SGCM)
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The electro-hydraulic power steering (EHPS) module
DIAGNOSTIC AIDS
IMPORTANT: The scan tool communication with the modules connected only to high speed GMLAN data link requires the use of the CANdi
module. Due to configuration of this vehicle, they may be communication DTCs set against modules that are able to communicate with the scan tool.
The following conditions may cause a total loss of high speed GMLAN data communication:
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A short between high speed GMLAN (+) and high speed GMLAN (-) circuits
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Any of the high speed GMLAN serial data circuits shorted to ground or voltage
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A module internal malfunction that causes a short to voltage or ground on the high speed GMLAN circuits
TEST
