XK (X100) V8-4.2L SC (2003)
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Supercharger Coolant Pump: Description and Operation
Charge Air Cooler Water Pump
The charge air cooler water pump monitor has been implemented to prevent engine damage, in the event of water pump failure. The monitor is only
present on supercharged variants and operates continuously during each drive, with a sample rate of 2.048 seconds. The basic operation of the monitor is
to compare the value of the intercooler IAT 2 against the IAT 1, at the end of a period of steady state operating conditions. Once the defined steady state
conditions are satisfied, a drive delay counter is incremented. Upon exceeding a calibrated threshold, if the difference between the two temperature
values (IAT 2 - IAT 1) is greater than the mapped threshold, a failure counter is incremented. If the counter exceeds a calibrated threshold, a failure
judgment is made. A normal judgment is made if the two temperature values are below the failure threshold, at the point of judgment.
