The OBDII check engine code P0171 will trigger the Malfunction Indicator Lamp (MIL) and this GM trouble code is indicating that there’s something wrong with your Cadillac’s fuel trims. More specifically, the code is for Bank 1 in your engine running too lean, or not having enough fuel for safe operation.
The causes behind this code can be varied, because so many sensors and inputs go into the equation of how much fuel is needed for your engine to run. Today’s DTC Doctor article is for My Pro Street user jamx_jims who has a specific question on how to replace the mass air flow sensor in a 2013 Cadillac ATS.
Although we’ll be showing you how to service a Cadillac ATS MAF in this 3.6 liter Cadillac LFX V6 engine to resolve the P0171 issue, there can be many possible other factors that could be causing your code.
This lean condition can cause your Cadillac to enter limp mode if the lean condition is severe enough. Possible issues with your intake or fuel components may be playing a huge role in your flex fuel Cadillac, or in this case the MAF.
If this code is triggered during a drive cycle, the chances of your LFX engine running lean during closed loop operation is high. Most of the time this issue can be traced to a leaky intake boot or vacuum leak that is causing unmetered air to enter the engine.
Possible Causes of GM P0171
- Leak after the MAF
- Bad 02 Sensor
- Ignition coil issues
- Fuel pump failure
- Improper fuel pressure
- Backwards LFX PCV Connection
If the air intake leak is severe enough and occurs after the mass air flow meter, that means that large amounts of unmeasured air that your PCM was not anticipating is entering the combustion chamber. This causes the excessive lean condition, and must be remedied if you want to prevent long term damage to your LFX engine.
To check for intake leaks use a small spray bottle filled with soapy water to gently spray onto your intake tract. If there is no intake leak condition, replace your air filter element and then check your Mass Air Flow Meter.
Today we’ll be showing you how to service a Cadillac ATS MAF to resolve the OBDII trouble code of P0171 in a 2014 Cadillac ATS V6 with the E85 flex fuel option.
Where is my MAF?
Your ATS Mass Air Flow Meter is located next to the air box on the driver side of the vehicle. You will need to locate your MAF by tracing by the wiring connector to the MAF, and pulling out on the red locking tab on the connector.
Once this red locking tab is pulled out, you can unplug your MAF and begin to undo the screws to your intake snorkel.
Once you have this plug undone, you can simply undo the hex screws and replace the Mass Air Flow Sensor (MAF) unit completely. If you are replacing the air filter element and / or cleaning the MAF or MAF housing, you must loosen the clamps that secure the intake snorkel.
With these two clamps loosened, you should be able to slide the accordion intake snorkel out by compressing it together. If you need a How to Replace your Air Filter for the Cadillac ATS, make sure to check out our guide here.
Once you have the MAF sensor replaced, reconnect the harness and depress the red locking pin to secure the unit. You now know how to service a Cadillac ATS MAF, and this should resolve any MAF related issues that could be leading to your P0171 condition.
If your OBDII trouble code persists, you could have issues with your oxygen sensor which could be feeding the wrong information to your Cadillac PCM. This could result in your PCM misdiagnosing an overly lean condition, leaving it unable to adjust for closed loop or part throttle driving.
Have any questions or comments about our How To Service a Cadillac ATS MAF Guide? Let us know below
[…] with your 02 sensor or your ECU. The most common OBDII trouble code for this error is P0171, check here for how to replace the MAF sensor in your Cadillac […]