You are here: Check Engine Light Home > Chevrolet Check Engine Light Questions & Answers

ChevroletChevy/Chevrolet Check Engine Light Questions

This page will list all the Check Engine Light questions and answers asked of us pertaining to Chevy vehicles. Some Chevy vehicles include Silverado, Suburban, Cavalier, Trailblazer, Tracker, Tahoe, Cobalt, and more.


2003 Chevy Silverado 1500 P0327 - I accidentally sank the truck in a creek and now I have a P0327 code, what is the problem?


2003 Chevy Tahoe 5.3L P0135 Engine Light Code - I have a 03 Tahoe with a P0135 code that won't go away. Help!


2004 Chevrolet TahoeQuestion: I ran out of gas in my 1999 Silverado. I put in gas and now my Check Engine Light is on. It is running fine and the same before the incident. Is there a problem that I may have created that need to be looked at? - Matt, December 2008

Answer: Hi Matt. Yes, your truck does need attention. When the truck ran out of gas it likely set a misfire code, and possibly other codes. It should be safe to just clear the trouble codes. If any engine light codes return, the truck will need further attention. Good luck!


2004 Chevrolet TahoeQuestion: Hello, I drive a 2004 Chevy Tahoe 5.3L z-71 V-8 4wd 70000plus kms my problem is i got a code which read P0300- misfire.so i replaced all the plugs which where all black, i changed them @50000km before that.i tested the plug wires they were good.i changed the oil and filter which smelled like gas. going throw gas like crazy one day when the problem started, engine lite came on at the time it started to give me trouble. idol rough try too stall out.smelly exhaust.after i replaced plugs and oil it ran good for 10 minutes @ idol then engine lite came back on and the same code showed up. i check my oil again and it is black again and smells like gas.tries to stall again and idols rough.i was told it maybe my o2 sensors , and was told too disconnect all four of them. should i do that? and for how long can i do that for? would this stop it from gas getting into the oil then? WHAT SHOULD I DO ? - Darryl, December 2008

Answer: Hi Darryl. Based on what you've told me about your P0300 Random Misfire problem, this appears to be beyond simply replacing plugs, wires, and coils. Typically those are the first things to check. Other things to check normally include the fuel injectors themselves. The fact that gas seems to be going into the engine somehow is definitely concerning. If gas is getting into the crankcase then your O2 sensors should not be your next concern. There are quite a few things to check - compression, valves, intake manifold gasket, etc. and if you aren't up to the task it might be better off to take it to an experienced, trusted technician for a proper diagnosis, even if you perform the repair yourself. If you want to continue diagnosis, here are some things to read first - P0300 @ OBD-Codes.com; P0300 @ Engine-Light-Help.com; P0300 @ HotRodLane; P0300 at RandomMisfire; Good luck!


2001 Chevy SuburbanQuestion: 2001 chevy suburban 2wd 5.3l rough idle/stalling. "check engine soon " light on. Wanted to know how many oxygen sensors there are and where they are located. Thanks - Lonny, October 2008

Answer: Hi Lonny. Whoa there fella! Don't just go off replacing parts without diagnosing them properly... please! Get the engine codes read using a scan tool / code reader and go from there. It's entirely possible the problem has nothing to do with O2 sensors. It could be fuel or ignition related. Read the codes and then do a search here on them, that'll give you a place to start. Good luck.


2001 Chevy TahoeQuestion: How do I fix "KNOCK SENSOR 2 CIRCUIT LOW input bank 2"? My check engine light is staying on. I have a 2001 Chevy Tahoe. - Onnie, September 2008

Answer: Hi Onnie. Your code is a P0332 Knock Sensor 2 Circuit Low Input (Bank 2). With a code like a P0332 you're likely to find the problem lies with the knock sensor on bank 2 (that's the side of the engine that doesn't have cylinder #1), or with the associated wiring & connections. Start by inspecting the wiring and connectors, repair as required. If everything is fine, check the sensor using a DVOM (digital volt ohm meter). Replace if necessary. You can find the proper resistance values using a repair manual or comparing the sensor reading on bank 2 to that of bank 1. Good luck with your knock sensor issue!


1999 Chevrolet SurburbanQuestion: 1999 Chevrolet Suburban 2500 454 cid 7.5 L. Ran fine two weeks ago, check engine light came on, then soon after check gauges light came on. Oil pressure dropped down when I stopped, then came back up while driving. Seemed a little low. Truck was running fine. This week hooked up the camper started to tow. Loss of power and sputtering. Stopped at Auto Zone to diagnose. Code showed running rich. Cleaned MAF sensor and treated gas (thought I had some cheap gas). No change. Took the beast to a shop. They thought the crankshaft position sensor was bad. Tried 3 new ones. All didn't change a thing. Some wouldn't work. They gave up. Next off to the Dealer. Started out with the CPS, moved on to cylinder compression, the to the low oil pressure. They have come up with good pressure with pressure gauge. Now back to the CPS. They say the crankshaft if moving ever so slightly that it's messing with the CPS. The solution they came up with is New Crate Motor. $6800.00 What!!!. Help me please. - David, September 2008.

Answer: Hi David. Considering two technicians have already seen the vehicle up close and done thier own diagnosis, I'm not sure I'll be able to be of much more help. I will give you my comments however. You didn't say how many miles are on the Chevy, but given it's nearly 10 years old and the symptoms I'm going to guess the miles are starting to get up there. I suspect that you had a minor issue and the extra load on the engine (towing) caused whatever it is to finally fail. I can't really say whether you need a new crate motor or not (haven't they heard of rebuilt engines? LOL). I guess the question now is how much do you want spend. The vehicle is obviously in need of repair. Maybe it's time to trade or sell it? Can you do any of the work yourself? Perhaps you need a third opinion, but I suspect that's not going to be much help either. Is the Check Engine Light still on? Maybe you should get the codes read again and then look them up. Good luck!


2004 Chevy TrailblazerQuestion: I have a 2004 Chevy Trailblazer EXT 6 cylinder. Lately, my interior temperature gauge has been showing the outside temperature as being anywhere from around 0 degrees to -10 degrees. This is when the outside temps are actually around 75-80 degrees. I am guessing that one of the ambient air temperature sensors may be bad. What do you think? Also, if it were the sensor, where would I find it if I wanted to replace it myself and is it an easy job? This sensor problem is wreaking havoc on my auto climate control in the vehicle. It isn't a problem to turn it off, but it is an inconvenience I would like to fix. Thank you for any assistance you can provide. - JD, September 2008

Answer: Hi JD, thanks for contacting us. It sounds like the sensor to me. It should be located behind the grille in front of the radiator. You can buy them anywhere, RockAuto has them for about $5 without the bracket or $18 with it. I'd recommend inspecting all the wiring and connectors leading to the sensor before replacing it. If you have the factory specs, you could even check the resistance of the sensor to determine whether it's working correctly or not. Other possibilities include a sensor that's really dirty (muddy), a short in the wiring, etc. The photo below shows the sensor (with bracket), that's what you're looking for. Good luck!

Ambient Air Temperature Sensor


2002 Chevy TrackerQuestion: I have a 2002 Chevy Tracker. A month or so ago I lost the gas cap and drove around for a day without it. The service engine soon light came on which is when I checked and found out that the cap was off. I bought a cheap cap and put it on. Shortly after that, the light went out.

After a couple of weeks the light came on again and stays on all the time. Took it to autozone and they came up with code P0031 and definition: 02 heater condition-check repair resource for sensor location and identification, also and explanation "the powertrain control module controls the electrical circuit for the oxygen sensor heater. The computer has recognized a failure in this circuit." Is this code related to driving without a fuel cap for a day or something else? (Do I need to bring it to a mechanic and what would an honest mechanic do and cost to follow up on this code check from the parts store? - Brenda, August 2008

Answer: Hi Brenda! If you left the gas cap off, it would likely trigger an emmissions related code, P04XX. I've seen many cases where a cheap replacement gas cap causes more trouble codes though! I would highly recommend you replace that cap with a quality OEM Chevy one soon.

As for the P0031 code (HO2S Heater Control Circuit Low Bank 1 Sensor 1) specifically, it's indicating a problem with the upstream oxygen sensor heater circuit in front of the catalytic converter. Since the code refers to the circuit, simply buying and replacing the oxygen sensor won't definitely fix the code.

The code is set because there is a problem with that oxygen sensor heater circuit. If you aren't able to fix it yourself, then definitely take it to a trusted technician. I can't say what they would charge but they would need time to properly investigate & diagnose the circuit. If the oxygen sensor proves to be faulty, it would take longer to replace that. So a ballpark guess would be 2 hours of labor. It may be more or less. I hope this helps!