P0171b?

[21Rouge]

I had a solid yellow engine light come on earlier this week (2005 Vibe MT)

I left it with my independent mechanic and he emailed me that the code shown is P0171b system lean bank.

(He says the idle is at 1200 rpm).

Can someone tell me what specifically what this code refers to specifically?

[gtv237]

It means that either unmetered air is entering the engine or there is a lack a of fuel.

[21Rouge]

It means that either unmetered air is entering the engine or there is a lack a of fuel.

Thanks for the quick reply 'gtv'.

In the little that I drove it after seeing the light there were no driving issues at all.

What would you suggest one check re either of these seemingly unrelated issues?

(What is the usual idle for an 05 Vibe?)

[vibrologist]

warm idle should be near 800 rpm, maybe as low as 750 rpm. My automatic does 800 when I shift into N.

First thing to do when the lean code appears: look for vacuum leaks anywhere between the MAF sensor and the cylinder head. Also go back on all the vacuum hoses, and don't forget the PCV system. Even the oil filler cap could be a source of vacuum leaks.

If there are no vacuum leaks, check the fuel pressure and injectors.

Check the DBW system.

[21Rouge]

warm idle should be near 800 rpm, maybe as low as 750 rpm. My automatic does 800 when I shift into N.

I guess it makes no difference manual vs automatic?

If there are no vacuum leaks, check the fuel pressure and injectors.

Can be a pain solving a high idle .

[circuitsmith]

Perhaps leaky intake manifold gasket.

[21Rouge]

Does the 05 Vibe have an air intake temperature sensor or is it incorporated with the maf sensor?

[21Rouge]

Perhaps leaky intake manifold gasket.

The mechanic replaced just today the intake manifold gasket (hard and cracked and leaking oil)

[vibrologist]

Perhaps leaky intake manifold gasket.

The mechanic replaced just today the intake manifold gasket (hard and cracked and leaking oil)

There you go! I replaced mine even before I had a CEL on. It was idling rough when warming up and ran smooth when warm. That does not mean that I am smarter than OBDII , I had experienced this with a Ford Windstar before.

[Salsa Guy]

The 05 were not really affect by a leaky manifold gaskets 03-04 were. You have a 10 y/o car and not sure what inspections and maintenance you have done but start with hoses and clamps around the intake and TB. Use a Carb Cleaner to isolate the issue.

[joatmon]

could it also be caused by a dirty MAF sensor?, at least that's easy to clean

[21Rouge]

Thanks for the help everyone.

Replacement of the MAF sensor seems to have resulted in a lower idle...about 900 rpm (colder days).

[vibrologist]

The 05 were not really affect by a leaky manifold gaskets 03-04 were. You have a 10 y/o car and not sure what inspections and maintenance you have done but start with hoses and clamps around the intake and TB. Use a Carb Cleaner to isolate the issue.

Maybe they were not affected as much but they sure start failing now. The problem is the oil that get sucked up through the PCV system. It destroys the rubber over time. It is a really easy diy project and the gaskets are cheap to buy.

[circuitsmith]

The 05 were not really affect by a leaky manifold gaskets 03-04 were.

My 2006 had the black gasket, which I changed after 47k miles and 8 years.
No symptoms, but was pretty hard and was deformed in one spot.