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Hello all, I have had my 1997 C5 Corvette for over a year now, I noticed and engine light a long time ago but it disappeared so i thought not much of it as I had been doing work to it.
but recently whenever i give it a bit of gas the check engine light comes on. I've cleared all codes even when driving and the light goes away and then comes back not long after. and I immediately wrote down all the codes that came up. they are as follows
10-PCM P0151 H C ( HO2S CIRCUIT LOW VOLTAGE BANK 2 SENSOR 1)
10-PCM P0151 H (???)
10-PCM P1571 H (ASR desired desired torque) and another website says (TORQUE SIGNAL IS OUT OF THE VALID RANGE (SEE C1277)
99-HVAC B0338 H C (inside air temp sensor open)
AO-LDCM B2252 H (key cylinder switch fault)
BO-RFA U1096 H (NORMAL SOFTWARE FUNCTION, HISTORY STATUS UPON IGNITION CYCLING)
BO-RFA U1064 H (LOSS OF COMMUNICATION WITH BCM)
BO-RFA U1016 H (LOSS OF COMMUNICATION WITH PCM)
a mechanic friend of mine said that the 10-PCM P0151 H C ( HO2S CIRCUIT LOW VOLTAGE BANK 2 SENSOR 1) means that the oxygen sensor is heated, and that would be bringing up the engine light. but have no idea if this is faulty sensor or something else is triggering it.
All i can say is that I've noticed very slight imbalances in the power when my foot is down, doesn't seem to climb in power perfectly smooth, but this could also be me just picking up on things that don't exist, also there is a high pitched noise that sounds like a blow off valve almost, when i hit the throttle i can hear it for a moment before the car revs, and when i turn it off it sounds like some kind of air is dumping. but it has always made this noise. so I'm really not sure. car seems to operate and drive normally.
should i take it to a mechanic? do you guys have any advice or similar experiences, any help is appreciated i know its a whole lot of random codes but its hard for me to decipher what any of it means or how bad it is.
Casey, Do you have a scan tool or did you get these DTC's through the DIC ??...for your driveability issue I'd chase the P0151 which is a "C" or current code...you can have either a bad O2 sensor or wiring or something that is actually causing the O2 sensor "low voltage" or lean condition which means the engine computer is seeing less than 200mv on the O2 signal wire...this can also be a lean condition such as clogged injectors, exhaust leak, bad gas, a vacuum leak which MAY be the sound you are hearing...the sound would be more prevalent at idle when the throttle blade is closed and there is high engine vacuum then at wide open throttle when the vacuum is low...if you don't have a scan tool disconnect the PCV hose that is located behind the throttle body on the right side (see pic) and plug up the nipple coming off the manifold with a short piece of hose with the end plugged up...go for a ride and see what happens...there may be a big hole in the PCV hose...if you have a scan tool and can look at fuel trims we can go that route...I am moving this thread to Tech.
i got all the codes from the DIC, I will check the exhaust for leaks as it has been apart a few times and I didn't personally check to see if it was done correctly. I can disconnect and plug this PVC hose you have shown, but I'm not sure what I'm looking for when doing this. will this determine if that hose has a vacuum leak?.
thank you for your response, i will go through what youve said and see if i can find anyhing
cheers, Casey
after poking around, it looks like this is the pvc hose, its slightly different to the photo you have sent, probably due to year model of mine being older, should i just rip this out and plug it as you say. i have no scan tool handy, but could probably get one if it would help. cheers
I didn't know if you had a scan tool or not but if you did by plugging the PCV line to the manifold we can see if the fuel trims decrease denoting a vacuum leak...to check for an exhaust leak if you have a shop vac you can plug the hose into the other end so it blows air out and tape the hose to the exhaust (plug other 3 exhaust tips) and get a bottle with soapy water then turn the vac on and spray the suspected area…right cylinder bank in your case...I find this method works best !!...also remove the shop vac filter if you can too. Since you were playing with the exhaust system that would be the first place to look....also it really helps to own a scan tool to help diagnose issues with these cars !!
I will definitely try out the vacuum method, its a really good idea. and ill see if i can get my hands on a scan tool. ill try these out and update this thread soon. thank you so much for your help
I will definitely try out the vacuum method, its a really good idea. and ill see if i can get my hands on a scan tool. ill try these out and update this thread soon. thank you so much for your help
if you’re located in So Cal I can assist with a scan tool. If not, I’d try Harbor Freight for an inexpensive option that will come in handy many times with these older cars.
if you’re located in So Cal I can assist with a scan tool. If not, I’d try Harbor Freight for an inexpensive option that will come in handy many times with these older cars.
Just checking but, I am pretty sure C5 Diag meant that you could plug the PCV fitting TEMPORARLY just to see if it was the source of the noise. It almost sounded like you were just going to cap it off permentaly. You CAN NOT or should not run the engine very long without a properly functioning PCV system. Testing is fine.
Our early C5s (97-2000) have a weird PCV hose behind the intake manifold. It branches off into a Y fitting. That Y and the hose is well known that it will dry rot and CRACK, & split and make that weird noise, It can also cause a rough idle and LTFT issues.
Something to check. Jack up the front of the car and set it on jack stands. Engine COLD. Turn the ignition switch to RUN (engine off) for approx 10 mim. After 10 min, CAREFULLY feel the base of each O2 Sensor. If everything is working properly, they should be VERY WARM to the touch. You could use an inferred temperature gun and read the BASE each sensor where they screw into the pipe. They should all read very close to each other if the O2 sensor heaters are working properly. .
Look in the engine compartment Fuse Box and find the OXY SEN fuse. Turn the Ignition Switch to RUN (engine OFF) On top of each fuse are Two Small Test Points. Use a multimeter and read each of the two OXY SEN fuse test points to battery ground. Compare battery voltage to the reading that you get on the OXY SEN fuse test points. The fuse test points SHOULD read battery voltage. If its LOW, please list the reading.
If you get a Scan Tool that has the ability to read LIVE DATA, you can use it to see if your primary O2 sensors are switching properly. After the engine is at operating temp and in closed loop the O2 sensors should switch between 100 millivolts to 900 millivolts (there abouts).
yes i am located in new Zealand but thanks for the offer on the scan tool. i will try both the pvc pipe plug to see if the noise stops and double check the fuses and sensors by jacking the car up, lots of helpful information here, really appreciate it. now i just need some free time to actually get them done, thanks all
hello after a few months of trying all kinds of different things such as replacing both oxygen sensors and getting the intake and exhaust checked for leaks, i am still getting the same engine light code come up randomly when driving
10-PCM P0151 H C ( HO2S CIRCUIT LOW VOLTAGE BANK 2 SENSOR 1)
the only thing i could not try was disconnecting the small pvc pipe that C5 Diag recommended as i have no access to a tool that can read live data.
the only other unusual thing i got was the ABS light and traction control light come on mid drive and the screen said "service vehicle soon" and once restarted never came back, but i know these cars do unusual things.
so as for the engine light im pretty stumped on what to do. should i just take it to a shop? or does anyone have any ideas. id really like to sort it out as i may need to sell it soon in order to move out of my parents house and it will be hard to sell a car with an engine light.
If you don't have a scan tool you are wasting your time trying to troubleshoot this issue. You need to know the o2 voltage and how it is switching. Otherwise you are just guessing what the problem is. You may have a wiring issue or the PCM is bad or maybe the sensor you installed is not working or other issues. You have been driving this way for awhile maybe damaging the engine, so just bring it to a mechanic.
Unable to diagnose engine light.
