Avalanche 4WD V8-5.3L (2011)
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Test all control module voltage supply circuits. Many vehicles have multiple circuits supplying voltage to a control module. Other components in
the system may have separate voltage supply circuits that may also need to be tested. Inspect connections at the module/component connectors,
fuses, and any intermediate connections between the voltage source and the module/component. A test lamp or a DMM may indicate that voltage
is present, but neither tests the ability of the circuit to carry sufficient current. Operate the component to test the ability of the circuit to carry
sufficient current. Refer to Circuit Testing See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing
and Power Distribution Schematics See: Diagrams/Electrical Diagrams/Power Distribution Schematics/Power Distribution Schematics Index.
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Test all control module ground and system ground circuits. The control module may have multiple ground circuits. Other components in the
system may have separate grounds that may also need to be tested. Inspect grounds for clean and tight connections at the grounding point. Inspect
the connections at the component and in splice packs, where applicable. Operate the component to test the ability of the circuit to carry sufficient
current. Refer to Circuit Testing See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing and
Ground Distribution Schematics See: Diagrams/Electrical Diagrams/Ground Distribution Schematics/G100.
Temperature Sensitivity
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An intermittent condition may occur when a component/connection reaches normal operating temperature. The condition may occur only when the
component/connection is cold, or only when the component/connection is hot.
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Freeze Frame, Failure Records, Snapshot, or Vehicle Data Recorder data may help with this type of intermittent condition, where applicable.
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If the intermittent is related to heat, review the data for a relationship with the following:
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High ambient temperatures
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Underhood/engine generated heat
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Circuit generated heat due to a poor connection, or high electrical load
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Higher than normal load conditions, towing, etc.
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If the intermittent is related to cold, review the data for the following:
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Low ambient temperatures-In extremely low temperatures, ice may form in a connection or component. Inspect for water intrusion.
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The condition only occurs on a cold start.
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The condition goes away when the vehicle warms up.
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Information from the customer may help to determine if the trouble follows a pattern that is temperature related.
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If temperature is suspected of causing an intermittent fault condition, attempt to duplicate the condition. Refer to Inducing Intermittent Fault
Conditions See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Inducing Intermittent Fault Conditions in
order to duplicate the conditions required.
Electromagnetic Interference and Electrical Noise
Some electrical components/circuits are sensitive to electromagnetic interference (EMI) or other types of electrical noise. Inspect for the following
conditions:
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A mis-routed harness that is too close to high voltage/high current devices such as secondary ignition components, motors, generator, etc.-These
components may induce electrical noise on a circuit that could interfere with normal circuit operation.
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Electrical system interference caused by a malfunctioning relay, or a control module driven solenoid or switch - These conditions can cause a
sharp electrical surge. Normally, the condition will occur when the malfunctioning component is operating.
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Improper installation of non-factory or aftermarket add on accessories such as lights, 2-way radios, amplifiers, electric motors, remote starters,
alarm systems, cell phones, etc. - These accessories may create interference in other circuits while operating and the interference would disappear
when the accessory is not operating. Refer to Checking Aftermarket Accessories See: Testing and Inspection/Component Tests and General
Diagnostics/Checking Aftermarket Accessories.
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Test for an open diode across the A/C compressor clutch and for other open diodes. Some relays may contain a clamping diode.
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The generator may be allowing AC noise into the electrical system.
Incorrect Control Module
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There are only a few situations where reprogramming a control module is appropriate:
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A new service control module is installed.
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A control module from another vehicle is installed.
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Revised software/calibration files have been released for this vehicle.
Note: DO NOT re-program the control module with the SAME software/calibration files that are already present in the control module. This is
not an effective repair for any type of concern.
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Verify that the control module contains the correct software/calibration. If incorrect programming is found, reprogram the control module with the
most current software/calibration. Refer to Control Module References See: Testing and Inspection/Programming and Relearning for
replacement, setup, and programming.