After Boil Coolant Pump Malfunction
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After Boil Coolant Pump Malfunction
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Circuit/System Description
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The auxiliary coolant pump and cooling fan system provides a measure of prevention against fuel vaporization due to excessive engine temperatures. The engine control module (ECM) commands the auxiliary or after boil coolant pump ON when the engine coolant temperature exceeds a calibrated value after engine shut down. The ECM applies ground to the coil side of the auxiliary pump circuit board (PCB) relay. This energizes the coil and applies voltage directly to the pump motor through the switch side of the relay.
Description and Operation
Cooling System Description and Operation
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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1.
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Ignition ON, observe the DTC information with a scan tool. Verify that DTC P2600, P2602, or P2603 is not set.
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2.
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If any auxiliary coolant pump DTC is set, repair the DTC first. Refer to
DTC P2600-P2603
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3.
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Ignition ON, command the Aux. Coolant Pump Relay ON and OFF with a scan tool. Verify that the G8 auxiliary coolant pump turns ON and OFF when changing between the commanded states.
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1.
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Test for a blockage or restriction in the G8 auxiliary coolant pump lines and hoses.
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2.
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Test the G8 pump coolant passage for a blockage or a restriction.
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3.
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Test the G8 pump impeller for a seized or binding condition.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
