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Best OBDII Code Reader for C5 (and C7?)

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Old Mar 27, 2022 | 12:04 PM
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Default Best OBDII Code Reader for C5 (and C7?)

Curious if anyone can recommend a good diagnostics code reader for our C5 that can be also used for later model years.

I know the DIC code reading procedure, however the DIC does not offer sub-codes for specific engine diagnostics, i.e., which valve and/or spark plug is not firing, etc.

i just swapped out all my plugs and wires and now have a rough idle and check engine light. Per the DIC code pull, I have an issue with one of the valves, just don’t know which one. Would rather buy a unit I can use for both my C5 and C7 than a dealership diagnostic or auto parts store.
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Apr 2, 2022, 03:56 PM
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OK. To close out this thread and hopefully pay it forward to other members, I purchased the Foxwell NT301 OBD2 Scanner for around $75 with S&H off Amazon and it worked great. It works for both my C5 and my C7Z and it also works to pull codes from my wife's 2021 Mazda CX-9 SUV.





By using the scanner, I was able to confirm that the DIC code 10 PCM P0300 was sub-identified as a Cylinder #5 misfire. (So happy it wasn't PITA #7).

I went in and removed the spark plug wire and plug from #5 and it was obvious that the original replacement AC Delco 41-162 Iridium spark tip was damaged during my initial installation. The Iridium plugs are pre-gapped so you can see the difference in the damaged plug on the left and the new undamaged plug on the right. I remember dropping it during installation, so the misfire makes sense.

Overall, not a bad investment to the tool box considering a dealership would have charged me at least $80 for the diagnostics, service and new plug.





Old Mar 27, 2022 | 12:20 PM
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Best for a C5 is the Tech-II (what the dealers used back in the day), but that's not so good for a C7.

The newer GM tools are good for the C7.

For a less pricey option, a good OBD app like Torque Pro with a high quality bluetooth or cabled OBD-II dongle (for both C5 and C7, I'd recommend the OBDLink MX+) will do a lot of diagnostic and performance monitoring. The dongle is under $100 (avoid the cheaper, slower ones as they can have issues, especially with newer cars like C7s). The apps are pretty cheap. Torque Pro is still under $10 IIRC.
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Old Mar 28, 2022 | 12:15 PM
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Agreed that a Tech 2 is the best option at least for a C5 (not sure if it's compatible with C7).
I went with the VX Diag VCX Nano which is a Tech 2 emulator. $129 (minus $8 coupon) on Amazon:
Amazon Amazon
There's a little bit of software to get situated on a PC but for me it's been awesome to get all the diagnostic data that you can't get with an OBD2 reader.

Last edited by MetalMan2; Mar 29, 2022 at 10:49 AM.
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Old Mar 29, 2022 | 09:01 AM
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The Tech2win running on a laptop (win7/10 or 11 together with a VCX Nano is recommend . I bought a extra 9 foot USB micro cable so I can move around the engineroom easily when testing stuff .

Here is a superb post on how to instal the software from the forum that may help on how to install
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Old Apr 2, 2022 | 03:56 PM
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OK. To close out this thread and hopefully pay it forward to other members, I purchased the Foxwell NT301 OBD2 Scanner for around $75 with S&H off Amazon and it worked great. It works for both my C5 and my C7Z and it also works to pull codes from my wife's 2021 Mazda CX-9 SUV.





By using the scanner, I was able to confirm that the DIC code 10 PCM P0300 was sub-identified as a Cylinder #5 misfire. (So happy it wasn't PITA #7).

I went in and removed the spark plug wire and plug from #5 and it was obvious that the original replacement AC Delco 41-162 Iridium spark tip was damaged during my initial installation. The Iridium plugs are pre-gapped so you can see the difference in the damaged plug on the left and the new undamaged plug on the right. I remember dropping it during installation, so the misfire makes sense.

Overall, not a bad investment to the tool box considering a dealership would have charged me at least $80 for the diagnostics, service and new plug.






Last edited by MSG C5; Apr 2, 2022 at 10:03 PM.
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Old Apr 19, 2022 | 06:37 PM
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I bought the NT301 after reading your post but found that it would not communicate with my 2004 Corvette. I, too, had the P0300 code and hoped to isolate the particular cylinder(s) throwing the code.

The scanner worked fine on my 2017 Santa Fe and 2009 Dodge RAM, connecting almost instantly with those cars, but would never connect to the Corvette!

Before using the scanner for the first time I updated the software to version 2.40.002

Is that the same version you were running?

Before I return it to Amazon, can you --or anyone else -- shed light on what went wrong?

Thanks.
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Old Apr 19, 2022 | 07:08 PM
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Check cigarette lighter fuse.
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Old Apr 19, 2022 | 07:15 PM
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My $12 Ebay scanner works fine on the Corvette -- just doesn't have the granularity I need...

Would that be affected by cig lighter fuse?

Last edited by decarmine; Apr 19, 2022 at 07:25 PM. Reason: added info
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Old Apr 19, 2022 | 08:57 PM
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It's probably the scanner then.
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Old Apr 19, 2022 | 09:08 PM
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Originally Posted by decarmine
I bought the NT301 after reading your post but found that it would not communicate with my 2004 Corvette. I, too, had the P0300 code and hoped to isolate the particular cylinder(s) throwing the code.

The scanner worked fine on my 2017 Santa Fe and 2009 Dodge RAM, connecting almost instantly with those cars, but would never connect to the Corvette!

Before using the scanner for the first time I updated the software to version 2.40.002

Is that the same version you were running?

Before I return it to Amazon, can you --or anyone else -- shed light on what went wrong?

Thanks.
Since it's compatible with the C5 it might be the scanner. Does it turn on but then not communicate. The NT301 is only an engine code reader so it won't read the ABS, transmission or SRS systems. A scanner like the Launch CRP123 will do that for many cars. It's a little more money but does alot more for you and can be used to troubleshoot all systems.
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Old Apr 20, 2022 | 12:00 AM
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I use this obd2 reader on all my cars to check/clear codes as needed

Amazon Amazon






Then I use the "engine link" app on my phone to work the reader via Bluetooth




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Old Apr 20, 2022 | 01:45 PM
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Originally Posted by decarmine
I bought the NT301 after reading your post but found that it would not communicate with my 2004 Corvette. I, too, had the P0300 code and hoped to isolate the particular cylinder(s) throwing the code.

The scanner worked fine on my 2017 Santa Fe and 2009 Dodge RAM, connecting almost instantly with those cars, but would never connect to the Corvette!

Before using the scanner for the first time I updated the software to version 2.40.002

Is that the same version you were running?

Before I return it to Amazon, can you --or anyone else -- shed light on what went wrong?

Thanks.
I didn't perform any update. I simply plugged it in to the OBD port and it worked. Below is the You Tube video I watched before using the unit.


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Old Apr 20, 2022 | 03:29 PM
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Originally Posted by MSG C5
I didn't perform any update. I simply plugged it in to the OBD port and it worked. Below is the You Tube video I watched before using the unit.

https://www.youtube.com/watch?v=ONR9fCn25Pc
OK -- thanks.

The update I did carried a Feb/2022 date so perhaps yours was an earlier version. Either the update I did caused the Corvette issue or I just got a defective scanner.

In any event I returned the unit to Amazon -- LOVE their "no questions asked" return policy.

I'm just gonna look for another scanner. The CRP123 recommendation above looks interesting, especially since it also checks ABS. My Hyundai has already had 2 ABS sensor failures which I was only able to ascertain after borrowing a much more sophisticated scanner...
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Old Apr 20, 2022 | 04:53 PM
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Originally Posted by C5MSG2004Vert
<snip> A scanner like the Launch CRP123 will do that for many cars. It's a little more money but does alot more for you and can be used to troubleshoot all systems.
Will the CRP123 show a live misfire condition? My son's Actron(?) scanner shows live misfire info on his 2008 Ford SportTrac but will not show live misfire on this '04 Corvette.

My original code was P0307 -- misfire cylinder 7. I then swapped ignition coils 5 and 7, expecting to see P0305, but since then all I've gotten is P0300 -- random misfires...

Last edited by decarmine; Apr 20, 2022 at 05:17 PM.
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Old Apr 20, 2022 | 09:44 PM
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Originally Posted by decarmine
Will the CRP123 show a live misfire condition? My son's Actron(?) scanner shows live misfire info on his 2008 Ford SportTrac but will not show live misfire on this '04 Corvette.

My original code was P0307 -- misfire cylinder 7. I then swapped ignition coils 5 and 7, expecting to see P0305, but since then all I've gotten is P0300 -- random misfires...
Your scanner has to be able to look at and show the mode 6 data. It will shows the total misfire counts by cylinder. The CRP123 does this. I used it to troubleshoot random misfires on my Mercedes C230. I believe it shows this for my C5. It's shows most if not all of the live sensor data like the
the steering wheel position sensor and wheel speed sensors. It can record the live data to an SD card.

Last edited by C5MSG2004Vert; Apr 20, 2022 at 09:49 PM.
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Old Apr 21, 2022 | 10:48 AM
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Originally Posted by C5MSG2004Vert
Your scanner has to be able to look at and show the mode 6 data. It will shows the total misfire counts by cylinder. The CRP123 does this. I used it to troubleshoot random misfires on my Mercedes C230. I believe it shows this for my C5. It's shows most if not all of the live sensor data like the
the steering wheel position sensor and wheel speed sensors. It can record the live data to an SD card.
Thanks.

I ordered the CRP123X -- similar to the 123 except has automatic VIN recognition. BUT -- says auto VIN works for "most 2004 and up..." So, worst case, I guess I'll have to enter the car info.

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Old Apr 21, 2022 | 05:23 PM
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Originally Posted by decarmine
Thanks.

I ordered the CRP123X -- similar to the 123 except has automatic VIN recognition. BUT -- says auto VIN works for "most 2004 and up..." So, worst case, I guess I'll have to enter the car info.
Hopefully the x is an improvement to the original one that I have. I have used mine on many cars and it seemed to provide access to all of the PIDs that the manufacturer provided for. A nice function is that when you use the manufacturer specific reader function by vehicle it will give the manufacturer specific obd2 code instead of the generic OBD2 code. Let us know how it works out.
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Old Apr 26, 2022 | 05:54 AM
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Originally Posted by C5MSG2004Vert
<snip> . Let us know how it works out.
Set up the LAUNCH CRP123X scanner and got live misfire info. Ran the car for about 30 seconds, saw about 4 misfires on cylinder 3, about 25 on cylinder 6, and more than 100 on cylinder 7. Since my initial code was P0307 -- misfire on cylinder 7 -- I changed that plug and wire first. As MSG C5 noted above, cylinder 7 is *definitely* a PITA!

Car is now running fine like it was before, and I'll change the rest of the plugs as time permits...

Last edited by decarmine; Apr 26, 2022 at 10:09 AM.
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Old Apr 28, 2022 | 11:19 AM
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All plugs have now been changed, scanner shows no misfires on any cylinder!

Last edited by decarmine; Apr 28, 2022 at 08:01 PM.
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Old Feb 4, 2023 | 08:45 PM
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Default Beware: Virus/spyware install from China on LElink

Originally Posted by jdmvette
I use this obd2 reader on all my cars to check/clear codes as needed

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1






Then I use the "engine link" app on my phone to work the reader via Bluetooth


Found this in the Amazon review. Old fashioned cabled OBD readers are still safest. Not fond with anything Bluetooth that requires app downloads. See review below:

Viruses and deceptive sales practices
Reviewed in the United States 🇺🇸 on April 13, 2015
I'm not surprised to see that this item was pulled from Amazon.

1. It comes with a CD that is loaded with viruses. Just for fun I spun up a virtual machine and let them go rampant on a firewalled isolated network to see what would happen. The viruses load a kernel module that hides their processes, then they create a text file with any personal information they can find on your computer, and attempt to connect to a server in China to upload the data over a FTP session tunneled through SSH.

2. The device itself is was sold using deceptive sales practices. It only supports three cars, and it only supports two of those partially.
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