P0171 and P0303

I have an 08 equinox with a 3.4L engine. I am getting a p0171 code and today while test driving I got a P0303 code which I am guessing is caused by the condition causing the 171 code. I know that the 171 code is referencing the egr system what I don't know is if they are typically the problem or do I need to look at something else first. I would appreciate any input.

Thanks!
rlanders

P0171 is a lean code for bank 1, P0303 is a misfire code for cylinder #3. Most likely you have a problem with #3 fuel injector as this would cause the lean code and misfire, or a vacuum leak at that cylinder. Probably an injector issue.

Thanks for the info, I'll check into the injector.

It could be an injector....could also be a bad wire, plug, or coil(3/6)....

I have an 08 equinox with a 3.4L engine. I am getting a p0171 code and today while test driving I got a P0303 code which I am guessing is caused by the condition causing the 171 code. I know that the 171 code is referencing the egr system what I don't know is if they are typically the problem or do I need to look at something else first. I would appreciate any input.

Thanks!
rlanders


Hello rlanders,

Is your Equinox currently exhibiting any concerns at this time? If so, we would be more than happy to look further into your situation for you. Just send us a private message with the following information for assistance: VIN, mileage, contact information, preferred dealership and additional details.

Have a wonderful day,

Helen
GM Customer Care

I have replaced the spark plugs and the pcv hose which was listed as most likely cause but I'm still getting the p0171 code. No longer getting p0303, however I did get c0561, p1779 and p0404. Any one with knowledge with these codes your advice would be appreciated.

I have replaced the spark plugs and the pcv hose which was listed as most likely cause but I'm still getting the p0171 code. No longer getting p0303, however I did get c0561, p1779 and p0404. Any one with knowledge with these codes your advice would be appreciated.

P1779 and C0561 are informational codes that are most likely related to the P0404. The P0404 is a sticking pintle in the EGR valve, also common on these as I have replaced many for the same C0561/P0404 combo. The P0171 could be a tough one to isolate. Be sure you are running a "top tier" fuel. Make sure there in no "unmetered air"(vacuum leaks or intake duct leak, exhaust leaks).

The EGR valve seems to be a common probable cause for the codes I've seen I was just hesitant to replace it without knowing for sure that it was the problem. Sounds like I need to go ahead and change it. Thanks for the info.

The EGR valve seems to be a common probable cause for the codes I've seen I was just hesitant to replace it without knowing for sure that it was the problem. Sounds like I need to go ahead and change it. Thanks for the info.

this is most likely the problem. The PCV hose does not securely fit the PCV. PCV is riveted into the engine . the 90 deg rubber connector swells up then you get a vacuum leak..the hose assy can be replaced or use a new 90 deg rubber piece .. I have had failures with these on other cars they do not last very long. the EGR would cause different codes.

I replaced the pcv hosee with a brand new one from the dealert but that did not fix the problem.

I would highly recommend replacing the EGR valve. It commonly causes the P1779, P0404, and C0561 codes as previously mentioned as well as the Service Stabilitrak/Service Traction Control messages as a result of said codes. You wouldn't be seeing C0561 if you weren't seeing those Service Stabilitrak/Service Traction Control messages. It is well documented on the Chevrolet forums that replacing the EGR valve usually gets rid of these issues on the Equinox w/3.4L engine. It took care of these issues on our Equinox when I replaced the EGR valve a few years ago.

The P0171 is another story. A bad EGR valve typically doesn't cause this. I saw that the PCV hose was replaced, but also check the brake booster hose along with the fitting that screws into the intake. The MAP sensor seal should also be inspected. If everything else checks out with regard to vacuum/intake leaks and exhaust leaks then you may have a bad upstream oxygen sensor.

Before doing anything else, replace the EGR valve with a good quality replacement. I recommend using AC Delco if possible. If the P0171 code persists after a few hundred miles of driving, then replace the upstream oxygen sensor in the rear exhaust manifold.

I appreciate the input.I guess I'll replace the EGR valve and see what happens. I'm not sure what else to try at this point.
Thanks Again!