I have been getting a P0131 for years now-many of us old timers have gotten it after changing air intake, along with the T/C light coming on. I got a P0171 twice, posted my problem. I removed the injectors and cleaned the bottom part (I have not taken them off the fuel rail yet), cleaned the MAF, and changed the air filter. For about 30 minutes I was code free, then they all began coming back on. I was advised to change the O2 sensor, and again for 30 minutes drove code free before they all came back. The problem now is that I am getting the P0171 frequently now, along with the standard P0131 code.

My impulse would be to get new injectors-they have 85,000 miles on them plus lots of extra hours from heavy-traffic driving in NYC.

Any thoughts on this? My inspection expires in 10 days. Thanks for any help you can give me.

Also, Don, I know you are very knowledgeable about our cars. I have 2 codes-PO301, cyllinder 1 misfire. I switched coil packs and put in 4 new plugs. Still code. Think it could be the injectors need to be replaced? Also, just got this new code tonight-PO171Generic misfire system too lean bank 1. What does this one mean?

Just did an internet search and thinking they could both be from a bad injector. They look easy enough to change-just remove fuel rail and they pop out.

For that P0171. Clean the MAF sensor first

https://www.obd-codes.com/p0171

"just" pop out is not exactly my experience. It takes some work and a new seal set.

I would do a compression check first before spending money on parts.

Will do, but no reason to think there are any problems. Car is running great except the idle has been rough and gas mileage has dropped lower than usual (for mostly city driving).And have had the number 1 cylinder misfire for a while-this could easily explain the po171 code also.

that P0171 usually is intake system related including vacuum leaks; a misfire usually give a specific code for that cylinder. Triggered by 1st downstream O2 sensor.

If you let it go it will turn into a bad catalytic converter.

If y'all read the link I posted, it could be a cracked flex pipe !
But first try the MAF cleaning!

Well, I have been checking for the past 4 days and have not gotten that PO171 code again. Only happened once. Now just getting the same PO301 code which I have gotten for a long time. I just put in a bottle of Techron fuel injection cleaner-maybe a miracle?

The issue which keeps giving me codes-TC and check engine- is that age-old problem so many of us have had. Back when the car was new, I began modifying it. I did each thing one at a time to check on performance and see the difference each made. First the exhaust-different muffler and added a y-pipe for dual exhaust. Then had the computer reprogrammed. Finally, added a CGS cold air package. A few days after that, I got hit by a speeding car directly in the right rear tire. Shortly after getting the car back from the body shop, I began getting the TC code (I don't think it happened before the accident.) At first, I only threw the code if the wheels spun, like from a burnout or wet leaves. After restarting the car a few times, the light would go out. But it got progressively worse. Next, it would code anytime I accelerated hard. Sometimes after hitting a bump or pothole. Next, just driving around then the light would come on. Finally, it happens randomly. I could be totally stopped at a traffic light or waiting for somebody, and the light will come on for no apparent reason.

In the beginning, this was a big topic on the forums. We thought it only happened to people who changed their air cleaners. At first, oil from the filter getting on the MAP or MAF sensor was thought to be the cause. I cleaned both, then replaced both. Next, it began happening to people with stock HHR's, with the factory air cleaner.

This remains a mystery to me. When the code throws, the car goes into limp mode, with the hard shifting. Then after a while, the light goes off by itself (or if I reset it) and the car is fine for a short while until it happens again.

Hmmm... I wonder if something was damaged in that accident? Wheel speed sensor, wiring? just enough to give you an intermittent problem.

https://www.chevyhhr.net/forums/prob...92/#post723591

That was my first thought-but keep in mind that many, many other people have the same TC code problem that have not had accidents. And remember that I do not have to be moving for the light to come on. Sometimes I start my car in the morning, let it idle for a few moments, and the light will suddenly come on.

Have you already changed the VVT valves? Could be one or both going bad.

Could be your tune is in need of updating.

Could be the wheel that got hit needs a new hub.

Could be a ground wire got loosened.

Could be the ignition switch is wonky.

Could be a fuse is loose or corroded underneath.

THanks Don for your insight. Two years ago, I changed something up top-I have to check my log book to be sure, but they dropped into the top. It was to correct a code so I could pass inspection back then. And, if I recall, it stopped the TC code for a few weeks. There was a recall for the ignition switch a while ago. Funny story-I bought one and put it in myself, but then had to do it over again and have the dealer do it to comply with some regulation crap. I have checked the fuses many times-there was an issue with them being loose and causing problems. I did change the hub and have checked all the wires and connections previously. I also checked the tune situation out around 6 years ago. I went to the shop, which was 3 hours from my house, and had them restore it to stock. I drove around for a while and still threw the code, so I had them put the tune back in.

What is the WT valve?

Again thanks for your help.

Variable Valve Timing. That is the typical cause of the traction light. Use of other than 5W30 oil can do it. Oil additives can do it.

Dirty or going bad MAF can cause your symtoms.

When you say the tc code do you mean that the traction control light illuminates? And if it illuminates it's just the traction light and not the check engine light? If so that simply means that the computer has set a soft or pending code. I had purchased an airaid intake and no matter what I did after a few pulls the code p0171 would set as a pending code with illuminated tc light. I tried everything I could and eventually ended up having to sell the intake system and go back to stock. I have a 2006 2.4 and think that the early 2.4 were a bit finiky

I just checked again, and no PO171 code anymore. Could it just have been a fluke? Still have to switch my injectors to see if the cylinder 1 misfire moves.

Question-when changing injectors, do you have to bleed the system afterwards, or can I just swap them?

3 days ago (Monday) I pulled off the fuel rail and cleaned the soot off of all 4 injectors. I also cleaned the MAF sensor and changed the air filter. Then I cleared all the codes from the computer. For the next hour, I drove around and there were were no codes. The car idled smoother, and all seemed great. Then, one by one, the 3 lights came back on (TC, ABS, and check engine). Some, like the TC, came on while the car was not moving-sitting at a traffic light. When I checked for codes, I had 4-2 for P0131 and 2 for P0171. I had only gotten that code once before, about a month ago, then never got it again until Monday. Since then, I have checked for codes 3 times a day, and only get the 131 code.

The car has 84,000 miles on it. How long do fuel injectors last? The engine has more hours on it than the miles predict-lots of city driving and lots of the car just idling while I wait for people (either to keep the heat or A/C on).

I need to get this resolved in the next 2 weeks so I can pass inspection.

Thanks for any help you can provide

Check for exhaust leaks: cracked flex pipe, bad exhaust manifold or gasket(s). https://www.chevyhhr.net/forums/prob...ry-sick-58231/

No exhaust leaks. No sound or exhaust fumes. Like I said, only got the P0171 two times-more concerned with the P0131, which I am hoping is just an injector. Next, if it is as simple as I think, I will switch around the injectors to see if the code changes to a different cylinder. Just need to make sure I can just move the injectors with out bleeding the system, or anything else.

P0131 has absolutely nothing to do with A/F ratio! It has to do with voltage to the #2 sensor.

You do need to relieve the fuel pressure before you get into the injectors. Just a rag over the Schrader valve to suck up an oz of fuel.

The p0171 is causing the TC warning.

Bleeding the injectors is a diesel thing.

Thanks, now I can try switching the injectors. I checked again and only got P0131 again w times. Like i said before, the 171 only happened 2 times but I have had the TC problem since 2006 when I installed the cold air filter. But, since people with stock air filters also get the code, not sure why.

Would love it if the O2 sensor is all that is causing the code. How can I check? And what is the #2 sensor?

I am old school and know nothing about these electronics.

Thanks again for all the insight and help

Here is a link I got from "p0131" in GoOgle.https://www.obd-codes.com/p0131

I was incorrect earlier it is O2 sensor #1. It could be the wires are compromised or the sensor is bad. It is possible that it is the cause of the P0171 in the past, before it gave up.

#1 sensor is the one closest to the engine.

Hi Don. In a different post, you told someone that unless his car was a 2006, you could see the sensor by looking down by the firewall. My car is an 06. What is the difference? Can I get at it from under the hood, or do I need to get under the car? I am assuming the flex pipe is not cracked or leaking because there does not seem to be any exhaust leak. I hope I am right. Again, thanks for all the help. Lord, this motor is so much more complicated (sophisticated) than the SBC in my race car.

Some 2006 cars have the O2 sensor bung on the manifold other years have it on the pipe. You should be able to see it from the top either way. If it's on the pipe you may be able to replace it in situ, actually easier to take the pipe out. The locks on the electrical connections are challenging.

One member managed to detach his bicep trying to do it in the car.

The problem could be the wires are laying on the exhaust.

Neither of these look exactly like I remember, but close enough.

Attachment 21115

Attachment 21116

Thanks again. Checked this morning, and 3 codes-2 for the P0131 and once for P0171. The O2 sensor looks easy enough to change, as long as it is not locked in from the heat. One article said to use WD40 on the threads before installing the new one. I was thinking Antiseize compound. What do you recommend?

Also, wide range of prices. I assume the AC/Delco is the way to go....

What would I do without you?

WD40 to get it out, New ones usually come with the right stuff, either in a tube or pre-applied.
My only brand advice is stay away from Bosch or any brand that is way too cheap. I think AC/Delco is actually made by NGK/NTK.

That boot is crumpled because your wheels are not pointed to the left. Rack & pinion. Normal. That is what tie rod ends are for.


The circled bit is supposed to be where the hose clamp is. The clamp is OK.
Attachment 21118

I changed the O2 sensor this afternoon. and for about 30 minutes drove code free, then the TC light popped up. A few minutes later, I got the check engine light came on. I checked the codes, and had 2 for T0131. I know it was long overdue to change that sensor, with 84K miles on it. But I think my injectors also need to be replaced. I could try switching them to see if the code changes to another cylinder.

I think that's a typo, if you meant P0131, then look at the wire harness for loose or damaged pins and wires.
As Don points out it might have melted if it touched the exhaust manifold or pipe!


https://www.obd-codes.com/p0131

Well, my wires all looked in good condition, and they were securely attached and not heat damaged.
I have been checking several times a day, and still keep getting the P0131 code. Worse, I just got that blasted P0171 code once the last time I checked.

P0131 isn't injectors, read this

https://www.obd-codes.com/p0131

Look at the wiring harness and connections to the first O2 sensor

For the P0171 you've addressed the fuel injectors, now check the other causes, like exhaust leak prior to the O2 sensor, like the flex pipe or the gasket from manifold to the down pipe

https://www.obd-codes.com/p0171

All I can offer is this GoOgle search for "p0131". https://www.google.com/search?q=p0131&ie=utf-8&oe=utf-8

There have been 3 other citations of p0131 with p0171 in the 10 years of this forum, all of them turned out to be an exhaust leak before the #1 O2 sensor or a wet/fouled wire.

My P0171 Came up in my attempt to change out my stock air box for an aftermarket Airaid kit. Even with everything tight and installed correctly, the code would be thrown at the first sign of throttle given to the engine. Even Airaid didn't know what the problem was. Back when I had the issues. Nothing I did could fix the issue, and it was a dry filter. So, I had to sell the unit and go back to stock, haven't seen the code since. Isnt yours an 06 2.4 as well? do you have an aftermarket air intake system?

Thank you all very much for the input. I have a brand new oxygen sensor in the car, and still getting the codes. The wires looked fine. Is there a way to tell if the flex pipe is leaking? I dont smell exhaust under the hood, and it looks good.
My thoughts with the fuel injector-if one is not working properly, wont that cylinder run lean? Wouldnt that throw the code also? I am not trying to be difficult or argumentative. I am just trying to understand what is going on.
Again, thanks for all your help. Also again, I wish I had dropped a SBC in. So much simpler to understand...

I thought you already messed with the injectors. That would be the end of my list, they don't go bad that often.

It may be a good idea to remove the downpipe and closely inspect the flex pipe. Doesn't seem too difficult, unless the fasteners are all rusted up.

https://www.chevyhhr.net/forums/how-...ex-pipe-31536/

Ok, folks, let's focus, Lee3333 you might not see the crack at the flex pipe , if it is cracked it will cause your lean condition, I drove all the back from Florida with a cracked flex pipe, I repaired the damaged part , codes gone.
We suggest this because the injectors don't usually cause problems. They are much more expensive to replace.

Hope I didn't step on any toes. I moved the code-related posts here, and left the waterpump-related posts in Lee's waterpump thread. Deleted a few posts about confusion. Now we're rockin' and rollin' again! :rocker:

Thanks RJ. Just trying to keep similar posts in the appropriate threads.

By the way, I did not totally remove or clean the injectors yet. Just took off the rail and cleaned the bottom part. I still have to check the top to make sure they are not clogged

From what I read, the flex pipe requires welding-not a simple fix

Yes, but the thread shows that's it's easy to remove, for inspection. If it's fine, put it back, on to the next item. If it's cracked, you have the options to weld, or to replace the whole downpipe.

Is there a way you can get an extension for your inspection? Even if you could find the fix tomorrow, your inspection is in, what, a week? And you still may need to complete some drive cycles before all systems are 'ready'. You are referring to a smog inspection, right?

I replaced the flex pipe it's part of the catalytic converter, 5 fasteners, easy fix.

2005 2006 2007 Chevrolet HHR Catalytic Converter flex down pipe 2.4 ** NEW ** | eBay