K 1500 Truck 4WD V8-4.8L VIN V (1999)
Use the Diagnostic Trouble Code (DTC) tables in order to locate a faulty circuit or component through the process of elimination. The Body
Control Module (BCM) performs a continual self diagnosis on certain control functions. A DTC will set when a malfunction is detected by the
BCM. The BCM will not turn the SERVICE ENGINE SOON Malfunction Indicator Lamp (MIL) lamp ON.
Intermittents and Poor Connections
Intermittent failures in electronic Systems may be very difficult to detect and accurately diagnose. For this reason, a good description of the concern may
be useful in locating an intermittent malfunction. Faulty wires or connections cause most intermittent problems. When an intermittent condition is
suspected, inspect the suspected circuits for the following conditions:
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Poor mating of connector halves of backed out terminals
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Improperly formed or damaged terminals
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Wire chafing
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Poor wire to terminal connections
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Dirty or corroded terminals
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Connector body damage
History DTCs are those indicating that the Body Control Module (BCM) has previously detected a malfunction. The reason could be either that the
malfunction is intermittent or that the system for which the DTC is set for is not currently being operated. For this reason, it the BCM displays history
DTCs and the malfunction cannot be found easily, try clearing the DTCs and manually operating the system that the DTC applies to using a scan tool.
Read the Diagnostic Aids and Conditions for Setting the DTC in each DTC table for more specific information.
History DTCs help in diagnosing intermittent fault conditions but do not necessarily indicate a faulty BCM. The BCM is a reliable component, and is not
the likely cause of the malfunction. Most system complaints are linked to faulty wiring and connectors, and occasionally to a component. Perform a
thorough inspection of all related wiring and connectors pertaining to the history DTC that is stored.
The following conditions may result in intermittent BCM operation with no DTC stored:
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Any condition which results in the interruption of power to the BCM
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The battery or ignition voltage is out of range (below 9.0 volts or above 16.0 volts).
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A loose or damaged ground
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An open or a short on the serial data line
