Pump, Coolant, Charge Air Cooler: Operation

Low Temp Radiator (LTR) coolant pump is used to circulate lower temperature coolant to cool down the intake charge air, the turbocharger, and the throttle body. The Powertrain Control Module (PCM) controls the LTR pump speed through Local Interface Network (LIN) to maintain Charge Air Cooler (CAC) coolant temp so that charge air temperature remains within an allowable range for engine functionality at high limits and CAC condensation at low limits. The operating pump speed shall be greater than a calibrated rpm low limit up to the maximum calibrated speed of the pump.