DTC P1299: Vacuum Leak Found: Testing
- Inspect the Intake manifold for vacuum leaks. Inspect the Power Brake Booster for any vacuum leaks. Inspect the Engine Closed Crankcase Ventilation (CCV) system (4.0L) or Positive Crankcase Ventilation (PCV) system (4.7L) for proper operation or any vacuum leaks. Were any vacuum leaks found? If yes, repair vacuum leak as necessary. If no, go to next step.
- The conditions that set the DTC are not present at this time. The following may help in identifying the intermittent condition. With the engine running at normal operating temperature, monitor the DRBIII® parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set. Review the DRBIII® Freeze Frame information. If possible, try to duplicate the conditions under which the DTC was set. Refer to any Technical Service Bulletins (TSB) that may apply. Visually inspect the related wire harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals. Were any of the above conditions present? If yes, repair as necessary. If no, test is complete.
NOTE:
This code is enabled on engines with plastic intake manifolds and is intended to shut down the engine if a large crack occurs. A large vacuum leak is mostly the cause of this DTC.
WARNING:
When the engine is operating, do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing.