Saturday I was driving home after getting my car washed from the hand wash place and my CEL came on. Went to Autozone to get it pulled and it was P0171. Popped hood to see that the metal clamp has fallen off my CAI to the throttle body. Was very loose. So I tightened it back onto the TB. Drove it this morning and the CEL is still there. Should I get the code cleared and see if it comes back or after running it for a while would it clear itself? I am not 100% sure it is that problem, but it is a step to get out of the way. Also a few months back I had my fuel pump replaced due to a gas smell leak and some gas lines. Any idea what else it could be if tightening the clamp doesn't work? Car has 48K miles. Have not changed the spark plugs/wires since I have owned the car at 20K. Do not feel it is necessary yet as the car is pretty much stock besides CAI.

 

Air leaks, vacuum leaks, etc, can cause a P0171. After the problem is fixed, the diagnostic has to run and PASS (and NOT fail) on 3 key cycles. Once that happens the MIL will turn off at the start of the 4th key cycle. My guess is you found and fixed the problem. 3 ~10 minute drives should be enough for the diagnostic to pass 3 times. 4th trip should be MIL free

 

Hi CrAzy,

Engine codes don’t typically reset automatically when a problem has been resolved. Often they require a number of cycles of proper operation before resetting. I also believe, although not positive, some require a manual reset. Hopefully, another forum member can confirm this.

You don't mention how many miles you've put on the car since installing the CAI or if the engine is performing well since you tightened down the clamp in spite of the code.

The code you mention indicates too lean a mixture on Bank 1. Now, on paper, that means you’re either getting too much air or too little gas. Now air leaks in the intake system can cause issues ‘though I can’t say for certain that the loose clamp is your root problem but if that one clamp was loose, it’s possible others are too.

I don’t suspect you have a fuel delivery issues and if the car is starting easily and running well, I wouldn’t worry about that right now. I also doubt the spark plugs need changing with 45 K and feel they would generate different codes but an inspection of the porcelain, electrodes and resistance can confirm that.

So before going into troubleshooting the air and fuel systems or bringing the car in for service, it’s best to start simple. Make sure the air system clamps and hoses are all tight and in order and get the CEL reset and see what happens. Now this assumes, and this is a big assumption, the engine is running strong without any hesitation. BTW, it wouldn't be a bad idea to buy a code reader as they’re not expensive.

You also didn’t mention if the car wash detailed your engine compartment, but if they did, I’d suggest you don’t let them do that in the future. Cleaners and the Hi pressure washes some shops employ are not good for the many electrical connectors and electrical components.

Good Luck and let us know what happens.

R~

 

Thanks for the long replies. I have only driven the car once since I fixed the clamp and that was this morning. After work today it will be a second key cycle. So I will just hold off a few more cycles and if it doesn't fix it I will take it in, clear the code and go from there. Again thanks for the lengthy reply. Learned something new today. I do wish they kept the C5 CEL to where you could read it off your DIC. Not sure why they removed it on the C6.

 

The clamp is the likely culprit. Tighten the clamp, clear the code, and see if it returns. Don’t wait for it to re-set, as it could take a while. Also, before you clear, check to see if the P0174 code is triggered as well.

The P0171 code indicates a lean condition in bank 1, meaning that your Long Term Fuel Trim values have exceeded the normal limits on bank 1. If in fact you had a vacuum leak ahead of the MAF, likely you also triggered P0174 which is the lean code for bank 2, as it is hard to imagine all the un-metered air wound up in just one bank only

LTFT’s are averages of the Short Term Fuel Trim readings over a period of time, and once you fix the problem, the short term values will return to normal immediately, but it will take some time before the LT average returns to normal. However, once you clear all codes, the LTFT values are cleared and the calculation starts from scratch.

Misfire and fuel system faults require three trips with “similar conditions” before the check-engine light is turned “Off.” These are trips where the engine load, RPM and temperature are similar to the conditions present when the fault was first found. So, not all trips will count, nor will any count while the LTFT values are still high.

 

The clamp was the problem. Fixed itself. All is good. to those who gave their input.