I scanned my car and found the following codes - C0501 and C0507.
I do not have a CEL or any other indication of a problem. The car drives great with no problems.
I recently installed Solar 91 Throttle bodies, Eventuri intake and Milltek HFC. I did get a CEL after the install due to the connection at the MAF was not tight.
I cleared the codes and everything went away, including the CEL. The codes remain.
If I did not have a scanner, I would not have any idea the codes exist. Is this something to worry about? Will the codes clear after several driving cycles?
Any help is greatly appreciated.

 

Well, the way one would properly address this is to use an advanced scanner like GMs MDI2 to see in detail what your car is telling you. Are these active or inactive codes? How many times were the codes set? Has the car attempted to run a self test to resolve these codes or has it already failed such attempts?

Depending on what is found, one would then run some diagnostic tests which might lead to troubleshooting to isolate the problem which could be something simple like a loose connector or a failed component. Without more information, no one can tell you what is wrong or what to do.

 

If you cleared the codes when you DID have a CEL, the codes you see now are probably codes in the history, and not currently active codes. Can't your scanner tell you the difference? Many can.

 

My scanner does not. Can you recommend one that does?
Thx

 

Can you recommend a scanner that does identify if the codes are active or inactive?

Thanks,

 

I use the OBDLink MX+ with my Android phone, but there are less expensive scanners that I'm sure will differentiate codes in history from currently active ones also.

 

It is a misconception that all DTCs will cause a MIL to be set even if they are active. The Malfunction Indicator Lamp or MIL (aka Check Engine Light) is actually part of the vehicle emission control system. Check it out in your Owner's Manual - that's what it says. It also says that in the Service Manual. There are DTCs set for an issue not considered part of the emission control system - and they may not cause the MIL to be lit. But they can still be active. The point is there are DTCs that do not cause the MIL to light.

The manual indicates these issues for the indicated coded.

DTC C0501 Left Front Wheel Speed Sensor Circuit Performance
DTC C0507 Right Front Wheel Speed Sensor Circuit Performance

 

Correct. OP states he had cleared the CEL and still found the two DTCs. This will probably show up in the My Chevy health report which is emailed to him and on the My Chevy app.

 

Thanks for the help.

 

I did a dyno test on the car, and I had a TC and ABS codes that went away. I read that these types of codes could show if the front tires are not spinning when the back are. Any thoughts?
I am still not sure of the fix.

 

I check the My Chevrolet app and it says all is good.
Is my next step to head to the dealer?

 

Not much more, no. The Service Manual sometimes gives detailed explanations about the conditions that cause a DTC to be set. For example - It could have said "this DTC is set if there is a discrepancy between the wheel speed and .....{some other speed like the the transmission speed or rear wheel speed] .." but it does not say that.

For those two codes, in the section on "Conditions for setting the DTC" it says only this:
"C0501, C0507, C050D, C0513
Debris on the component.
Incorrect installation of a component
Incorrect wheel speed sensor air gap
Electromagnetic Interference
The reluctor ring has missing teeth, magnetic segments, or indentations for a reference gap."

That list, unfortunately, sounds more like a list of possible causes, rather than an explanation the sensor measurements that led to the DTC being set. On the other hand, the diagnostic procedure the tech follows says, essentially as the first step during a test drive "All sensors must show the same speed when driving in a straight line at a speed greater than 40 km/h (25 MPH).....Verify the wheel speed sensor parameters are within 1.6 km/h (1 MPH) of each other". If this step checks out, the tech is done "All OK. A fault is currently not present and may be an intermittent condition." If not, then the tech goes on to test other things. That does not mean this is the specific condition that caused the specific DTC you see to be set. This diagnostic procedure is the same for a family of DTCs (15 of them actually). So there are different conditions that set each one.

I did come across a little more info of interest though. Earlier I made the point that non-emission control system DTC do not set the MIL. And that is true. But, for whatever reason, these two codes are a Type A DTC which the manual says are emission related. So, if that is right, you should see a MIL if the code is active. It also says that will turn the MIL off after 4 consecutive ignition cycles. It clears from history after 40 warm up cycles, it says. It also lists "action taken" when the DTC is set - it says
ABS Indicator Control on
Traction/Stability Control Indicator on
A message and/or warning indicator may be displayed to the driver.

Did you see any of those? I assume they would go away when the MIL is turned off.

 

I did a dyno test on the car before I lowered the car. After the dyno, I had a TC and ABS light. All lights or CEL are gone. I only see the problem when I do a scan.
I read on another thread that when you do a dyno, if the front tires are not rotation and the back do, you may get these codes. If I did not have a scanner, I would just keep on driving.
The car runs great, and it is much more fun to drive.
Thx

 

Yup, I think that's likely. They should clear on their own from history after 40 warm up cycles though. If they come back there may be a different issue.

 

Thanks, I have no problem putting on the miles!!
It would be nice if the weather would cooperate!! 42 and rainy does not help.