Codes P0171, P0457, and P0456

2009 DODGE AVENGER

126,000 MILES • 2.4L • 4 CYL • 2WD • AUTOMATIC

CHARLES THORPE

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Hello,

I had brought my car to AutoZone to get a check engine light reading and I had got three codes:
P0171
P0457
P0456
So I took it to the shop and my car has been there for two days going on three and they are saying they cannot find the problem.
They said they ran tests and everything is running fine which I find very hard to believe because my car has a rough idle rpm needle moves up a little and then down when in idle and when I first start my car I smell a strong odor of gas.
I really need some advice because I doubt that those codes popped up for no reason.

Oct 17, 2018 at 8:32 AM

ASEMASTER6371

CERTIFIED EXPERT
52,796 POSTS

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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Oct 17, 2018 at 8:55 AM