Good afternoon.
The 171 code is a lean running condition. That is usually either a vacuum leak or a fuel pressure issue. Have them do a smoke test on the intake for a vacuum leak.
The 456 is a common for the leak detection pump. Have them check the pump with a smoke test for a leak. Very common failure.
Also, have them do a bay test for the EVAP system.
Roy
DISCUSSION:
During evaporative system diagnosis, Leak Detection Pumps have mistakenly been replaced. A thorough inspection for pinched, kinked, or disconnected supply vacuum lines (as currently listed in the Powertrain Diagnostic Procedures) is a critical step in diagnosing DTC P1494 (LDP SW OR MECHANICAL FAULT). Additionally, the other evaporative leak faults (DTC P0442 - SMALL LEAK, P0455 - LARGE LEAK, and P0456 - VERY SMALL LEAK) should have the supply vacuum lines examined for pinches or kinks prior to any LDP component replacement.
The supply vacuum lines should be checked from the engine compartment all the way to the fuel tank, including the LDP and purge system.
Note:
Verify all related supply vacuum line routings for pinches, kinks, or disconnection's before replacing ldp system components.
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Wednesday, October 17th, 2018 AT 8:55 AM