What does that mean?
Basically this means that an oxygen sensor in bank 1 detected a lean condition
(too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of
the engine that has cylinder #1.
Note: This DTC is very similar to P0174, and in fact
your vehicle may show both codes at the same time.
Symptoms
You will more than likely not notice any drivability problems, although there
may be symptoms such as a lack of power, detonation (spark knock), and/or a
hesitation/surge on acceleration.
Causes
A code P0171 may mean that one or more of the following
has happened:
Toyota released a service bulletin regarding this issue concerning p0171. Basically the inlet manifold seal wasn't up to the job. The best place to start is to remove and clean the MAF sensor with spray alcohol. If p0171 persists check the pre-cat o2 sensor output using obd2 to see if the sensor responds to acellerator demand I.e. is the sensor responding. If so ask the dealer for a new updated seal. don't forget to ask for a throttle body gasket. Replace inlet manifold gasket-see YouTube videos. While you have the throttle body disconnected inspect connected air/vacuum hoses, they degrade significantly with age and heat. These are also easy to replace. Refit removed items. I found a hose perished. Then start engine and reset fault code using ODB2. The entire job took 40 minutes. No further fault code reoccurence. Hope this helps. In this instance p0171 code only happened after warm up, at idle.
SOURCE: 2006 Toyota Corolla Code P0171 What could be
po171 means the air fuel ratio is lean (not enough fuel) so you must check for anything that can do that a good example would be a vacuum leak that allows non metered air to enter the engine (more air same amount of fuel = lean mixture) or a clogged injector (same amount of air less fuel = lean mixture as well)
SOURCE: 2005 Toyota Corolla check engine light on.Fault
Hi
Could mean there is one fault causing many faults, example, Air mass sensor, this can cause rough idle and over fuelling so the code reader will just send it back with undefined as there are to many faults to identify as the cause.
Most likely it will be a air fault so check the air sensor first, try cleaning it with carb cleaner, sometimes works. If not get back to me could be 2 other things. although the car will not drive very well if it is any of the other 2.
Regards
Dan
SOURCE: Check engine light code P0171 activated on my 2001 toyota corolla
p0171 is lean condition bank one. you could have a vacuum leak a bad map sensor bad maf sensor clogged fuel filter low fuel pressure. start with the vacuum leak first.
SOURCE: I have a 2005 toyota
Now you have the O2 Sensor Code to diagnosed, to see
if it is bad or something caused it to go out of range
You really should only wait a couple days, to get any
System Malfunctional checked and repaired.
That is why the govt put the check lights on your dash
SOURCE: Toyota 2005 Corolla check engine
http://www.obd-codes.com/p0138
This may help you diagnose the problem
7,042 views
Usually answered in minutes!
×