TT 20-13-04

Tech Tips (3.6L ? MIL ON with DTCs P2400, P2404): This document informs for concerns of MIL ON and P2400/P2404. This can be caused by the change over valve on the water pump. The water pump has a vacuum controlled servo to control the flow of coolant. If the diaphragm fails, coolant can get into the vacuum supply line for the LDP pump. Vacuum test the port on the water pump. If it will not hold vacuum, replace the water pump and the vacuum supply line as necessary and retest operation.