Check as follows:
- Perform coolant pressure control cap tests; refer to EPA07 DD15 Workshop Manual (DDC-SVC-MAN-0002), “Cooling System” chapter.
- Check the test results.
- If the cap passes the test; refer to “11.4 Defective Coolant Hoses” .
- If the cap fails the test, remove and replace pressure control cap; refer to OEM guidelines.