07 Aura 3.6 V6 with P0171 P0174
Does anyone know the voltage range for the MAF Sensor from the factory diagnostic manual? I have an 07 Aura 3.6 litre with 178,000 miles. I'm not familiar with the vehicle and don't have any history. It had the DTCs: P0171, P0174, P0420, P0430 and P0700.
I cleaned the MAF Sensor with MAF spray cleaner, reset the fault codes, and drove it for 8 on/off drive cycles in about 30 miles, the P0171 & P0174 codes returned but the others did not.
I have checked for leaks around all the vacuum lines with Carb Cleaner spray up to the Power Brake Boost and located none. Since the ECM is sending both codes, the upstream O2 Sensors are working. It starts, idles, and runs well. Performance issues don't seem to be the issue. I haven't checked fuel pressure because I don't have a gauge and that seems highly unlikely that the fuel pressure is low. It also is not likely to be a fuel filter since it runs well. No exhaust leaks, Cat discoloration from excessive heat, rotten egg or excessively lean smell from the exhaust or indications of a partially blocked Cat. I can't detect an intake manifold gasket leak because I would have to remove the intake manifold to inspect it. A smoke machine would be great to check for intake leaks but I don't have one.
Do you know where the actual PCV valve is? The front bank has a connector on the top of the valve cover that runs to the intake piping from the MAF Sensor side, but it is just tubing. Is the actual PCV valve on the back bank? If this engine has a PCV valve, then it could be clogged and be a simple fix. Does your factory manual show a PCV valve and location? I found this online about the repair manual: "The Positive Crankcase Ventilation (PCV) valve is a fixed orifice system." I would still like to make sure it is not blocked.
It would be easy to replace the MAF Sensor, but I would like to test the voltage on the old one to see if it is within range. I'd rather not just start throwing parts at it hoping to get lucky.
I have a BAFX OBDII interface that connects to my phone using Torque Lite. Any help would be greatly appreciated.
I cleaned the MAF Sensor with MAF spray cleaner, reset the fault codes, and drove it for 8 on/off drive cycles in about 30 miles, the P0171 & P0174 codes returned but the others did not.
I have checked for leaks around all the vacuum lines with Carb Cleaner spray up to the Power Brake Boost and located none. Since the ECM is sending both codes, the upstream O2 Sensors are working. It starts, idles, and runs well. Performance issues don't seem to be the issue. I haven't checked fuel pressure because I don't have a gauge and that seems highly unlikely that the fuel pressure is low. It also is not likely to be a fuel filter since it runs well. No exhaust leaks, Cat discoloration from excessive heat, rotten egg or excessively lean smell from the exhaust or indications of a partially blocked Cat. I can't detect an intake manifold gasket leak because I would have to remove the intake manifold to inspect it. A smoke machine would be great to check for intake leaks but I don't have one.
Do you know where the actual PCV valve is? The front bank has a connector on the top of the valve cover that runs to the intake piping from the MAF Sensor side, but it is just tubing. Is the actual PCV valve on the back bank? If this engine has a PCV valve, then it could be clogged and be a simple fix. Does your factory manual show a PCV valve and location? I found this online about the repair manual: "The Positive Crankcase Ventilation (PCV) valve is a fixed orifice system." I would still like to make sure it is not blocked.
It would be easy to replace the MAF Sensor, but I would like to test the voltage on the old one to see if it is within range. I'd rather not just start throwing parts at it hoping to get lucky.
I have a BAFX OBDII interface that connects to my phone using Torque Lite. Any help would be greatly appreciated.
Last edited by TRW; Dec 22, 2024 at 08:29 PM.
derf - I'm new to this so not sure what you mean. I thought I was posting to a Saturn Aura thread. The top of this thread page reads "
- Saturn Forum - Saturn Enthusiasts Forums
- Vehicle Lineup
- Saturn Aura
- Aura with codes"
Last edited by TRW; Dec 21, 2024 at 10:44 AM.
You posted it on to the end of a thread in the L series section.
I moved your post and created a new thread for it.
You probably searched on MAF or something, looked at a post, then posted in that thread instead of creating your own in the Aura section
In the future, please create new threads for your Aura by navigating to tha Aura section of the forum and clicking on "create new thread." Only moderators can move stuff around the forum.
I'll get over it.
Thanks.
PS: Don't know the answer to your question.
I moved your post and created a new thread for it.
You probably searched on MAF or something, looked at a post, then posted in that thread instead of creating your own in the Aura section
In the future, please create new threads for your Aura by navigating to tha Aura section of the forum and clicking on "create new thread." Only moderators can move stuff around the forum.
I'll get over it.
Thanks.
PS: Don't know the answer to your question.
They could be any number of things. Just googling them I found this. Engine codes P0171 and P0174 indicate a lean fuel mixture in the engine, either in Bank 1 or Bank 2. The oxygen sensor triggers these codes when it detects too much oxygen in the exhaust.
Some possible causes of these codes include:
You can still drive with these codes, but you should avoid rapid acceleration and high engine speeds. It's recommended to have a repair shop check out the issue as soon as possible.
Some possible causes of these codes include:
- Vacuum leak: Air can enter the engine past the throttle body.
- Low fuel pressure: A weak fuel pump or a restriction in the fuel line can cause low fuel pressure.
- Dirty fuel injectors: Malfunctioning fuel injectors can prevent the engine from getting enough fuel.
- Exhaust leak: An exhaust leak before the oxygen sensor can cause the engine to appear to have too much air.
- Mass airflow sensor: A faulty mass airflow sensor can cause issues.
You can still drive with these codes, but you should avoid rapid acceleration and high engine speeds. It's recommended to have a repair shop check out the issue as soon as possible.
Do you know what the Fure Pressure Spec is? I'll look into renting a Fuel Pressure Gage tomorrow. Pretty sure it's not fuel pressure related because it runs too well and is gangbusters with the throttle wide open. Thank you.


