check engine light

[Brian Belt]

My check engine light came on today on my 2003 sport trac so I went by advanced auto parts so I could see which code would be displayed. The Tech said it was system too lean bank 1 and he thought the oxygen sensor needed to be replaced. Is there anymore possible causes? If so what are they? If not how hard is it to replace the sensor? Thanks for your help



Brian

 

[EddieS'04]

Post the code numbers here, Sounds like the guy was guessing. There are other things on these motors, that cause a lean bank.

 

[Jerry Gerner 2]

Too lean in bank 1 is usually the gas cap, evaporator hoses under the spare tire. On my '03 it's always the gas cap, I put a locking gas cap on it and it has a big O-ring on the shaft, sometimes that gets pushed down too far and will throw the code. I just take a key and move the o-ring up whenever I fill up make tank and it hasn't thrown that code since.

:banana:

 

[Brian Belt]

P0171 was the code. Thanks again for the help

 

[Jerry Gerner 2]

Let us know what happens and what you find.:banana:

 

[EddieS'04]

P0171 - System to Lean (Bank 1) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit. Refer to Section 1 , Powertrain Control Software, Fuel Trim for more information. Air Measurement System

MAF sensor (contaminated, damaged, malfunctioning, etc.)

Fuel System

Fuel pressure regulator (leaking, malfunctioning, etc.).

Fuel filter plugged, dirty.

Fuel pump (weak, check valve leaking, etc.).

Leaking/contaminated fuel injectors.

Low fuel pressure or running out of fuel.

EVAP canister purge valve leaking (when canister is "clean").

Fuel supply line restricted.

Fuel rail pressure sensor (incorrect reading).

Air Induction System

Air leaks after the MAF.

Vacuum Leaks.

PCV system (leak, valve stuck open, etc.)

Improperly seated engine oil dipstick.

Exhaust System

Exhaust leaks before or near the HO2Ss (exhaust manifold gasket, mating gaskets, etc.)..

EGR System

EGR valve tube/gasket leak

EVR solenoid vacuum leak

Secondary Air Injection

Damaged/malfunctioning secondary air injection system (mechanically stuck valve).

 

[David LaPlante]

Brian...Just ran into this last week with my 2003 (P-171 to lean bank 1) , ended up being the PVC tubing had to take it to the dealer and have them put it on the computer part was fairly cheap...they also cleaned the fuel and air system totaled out at 335.00. I can't complain it has been the first real repair money since i bought it in 2002....knock on wood.

 

[Kevin Palmer]

Code 171 and 174 lean is a result of a cracked PVC elbow.



It is allowing too much air into the system and thus, the mixture is lean.



Look here...

[Broken External Image]:



The crack is normally on the bottom of the hose.

[Broken External Image]:

 

[John Zuber]

See the smaller upper hose, just above the PVC elbow? It runs around the back of the engine and has a strange looking fitting. Almost like a small section of tubing bending around the PVC. Also, there looks to be a simular rubber elbow in this area too. What is this?

 

[Brian Belt]

It was a cracked hose. Thanks for the help guys.