K 2500 Yukon 4WD V8-6.0L VIN U (2000)
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Diagnostic Chart (Part 4 Of 4)
CIRCUIT DESCRIPTION
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information
and commands are exchanged among the modules. Connecting a scan tool to the DLC allows communication with the modules for diagnostic
purposes. Diagnostic trouble codes (DTCs) may be set due to this symptom and during this diagnostic procedure. Complete the diagnostic procedure
in order to ensure all the DTCs are diagnosed and cleared from memory.
DIAGNOSTIC AIDS
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When the class 2 serial data circuit is shorted to ground, U1300 will be set. Refer to DTC U1300 Class 2 Data Link Low.
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When the class 2 serial data circuit is shorted to B+, U1301 will be set. Refer to DTC U1301 Class 2 Data Link High.
TEST DESCRIPTION
The number(s) below refer to the step number(s) on the diagnostic table.
2. A partial malfunction in the class 2 serial data circuit uses a different procedure from a total malfunction of the class 2 serial data circuit. The
following modules communicate on the class 2 serial data circuit:
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Powertrain Control Module/Vehicle Control Module (PCM/VCM)