When too much air is in the system, it will run lean, and when too much gas is in the system, it runs rich.
The air gas ratio is managed by several components, including injectors, sensors, and the onboard computer (ECM/PCM).
This includes all Chevrolet Cruze engines such as the 1.4, 1.6, and 1.8 engines.
What Is a P0171 OBDII Code on a Chevy Cruze?
If you have a Chevy Cruze and get the code P0171, it is a generic OBDII code for “System Too Lean (Bank 1)”.
Some scan tools will also report the generic message “Fuel Trim System Lean Bank 1”.
The reason for this error is the onboard computer (ECM) is seeing the air/fuel ratio is wrong.
Also, the ECM sees the problem on BANK1, which is the side of the engine with the #1 cylinder.
Several things can cause a P0171 OBDII Code on a Chevy Cruze with the list below of common causes and fixes.
7 Causes and Fixes for Chevy Cruze P0171 OBDII Code
- Vacuum Leak
- PVC Valve
- Bad Oxygen Sensor
- Mass Air Flow Sensor
- Bad Fuel Injectors
- Fuel Pump/Fuel Filter
- Air Filter
Often there is a leak somewhere that causes the air/fuel ratio to be wrong and cause issues.
Finding a big vacuum leak is usually easy as it can often be heard, but a small leak can be problematic.
A vacuum test machine can be used which blows smoke into an engine and the leak found by the smoke coming out.
There are also old backyard mechanic tricks also such as using a can of starter fluid on an area to see if the engine idle changes.
Usually, a vacuum leak can be found with a bit of searching but if it can’t be found, using a smoke machine is the best option.
It is part of the vacuum and will usually make a hissing noise when it goes bad.
Example Chevy Cruze Valve Cover with PVC Valve Built in on Amazon
Valve Cover with Gaskets Bolts for Chevrolet Chevy Cruze Sonic Volt Trax 1.4L Buick Encore Cadillac ELR Replaces OE 25198874 55573746 25198498
The oxygen sensors send data to the onboard computer (ECM) for information on the air/fuel mix ratio, and the computer adjusts with this data.
If a sensor is bad, the data being sent is wrong, which can cause problems.
Usually, the upstream oxygen sensor is the one to go bad.
Often they become dirty and can be cleaned with MAF cleaner.
Of course, it can also go bad and need to be replaced.
If they become clogged or are not spraying fuel correctly, they can cause an issue.
Sometimes one or more injectors can become bad and spray 40-50 percent of the amount it is supposed to spray.
This will cause the fuel/air ratio to become bad, and the ECM will give a P0171 code.
A bad fuel pump or clogged filter will cause problems.
Usually, a bad fuel pump will not send any fuel, which causes the car not to start.
In some cases, it can become weak and not send out enough pressure.
The fuel filter may also be stopping fuel from passing through and going to the engine.
A dirty air filter will stop air from passing into the engine.
Often if the air filter is very dirty, it can cause other issues, such as causing the MAF sensor to become dirty also.
Can I Drive a Chevy Cruze with a P0171 OBDII Code?
Some cars will be drive-able while others are not.
It will depend on how bad the air/fuel ratio mix is off for how bad the car runs.
If it is drive-able, it will likely get worse and should be fixed as soon as possible.