Failed inspection. No reading from obd2. Help please

[southsidehustler]

So, I went to get an inspection sticker and their machine could not get a reading from my obd2. They told me that this is usually from a blown cigarette lighter fuse. So I checked both fuses, and tested both cigarette lighters and everything is good. I haven't had any issues with my truck. And I just took a test light to every fuse and everything is receiving power. I have been looking around for a loose wire or bent pin but I don't see any problems. There are 4 wires hooked into the plug. They are: orange, black/white striped, black, purple. I got the dmm and the orange is the 12v (it was reading at the plug), and it appeared that all the other wires were ground. I left the positive lead from the dmm touching the Orange and touched the negative lead on each of the remaining 3 wires and got a 12+ reading.
So, I am confused about what to do now. Can someone please help me understand what is going wrong and how I can fix it. Thanks a lot, because I am stuck.

[rtmsu_02]

srsly, i never had them plug into my truck to do an inspection in Louisiana....go to a diff place?

[csharp]

yea go somewere else that dont go on round here

[southsidehustler]

yeah, I can go somewhere else but I still wouldn't mind knowing what is messed up. ya know.

[rtmsu_02]

yea, go to auto zone and see if their reader works..... maybe a bad obdII scanner ?

[zuschke]

this is going to sound weird but..... here goes

I had the same problem on my 07 rado, the guy proceeded to open the fuse box and remove the fuse for the Radio. Then he hooked up to the OBD2 and everything worked perfectly. Then he put the fuse back in and i was on my way. Only issue was my radio stations being wiped out. The tech response was that he had to do that with a lot of colorados.

same thing happend when i was getting my tune. removed the radio fuse and.... it worked

i dont know if this will work for you, or why it works, or what the hell the radio has to do with anything related... never the less, good luck

[southsidehustler]

Thanks! I will give it a try tomorrow.

[rtmsu_02]

i have heard of that...the radio interferes with communications....when u get a tune, you should be asked to remove your radio fuse.....or at least every person i ever heard of has been asked.

[ssgjurista]

Originally Posted by southsidehustler

So, I went to get an inspection sticker and their machine could not get a reading from my obd2. They told me that this is usually from a blown cigarette lighter fuse. So I checked both fuses, and tested both cigarette lighters and everything is good. I haven't had any issues with my truck. And I just took a test light to every fuse and everything is receiving power. I have been looking around for a loose wire or bent pin but I don't see any problems. There are 4 wires hooked into the plug. They are: orange, black/white striped, black, purple. I got the dmm and the orange is the 12v (it was reading at the plug), and it appeared that all the other wires were ground. I left the positive lead from the dmm touching the Orange and touched the negative lead on each of the remaining 3 wires and got a 12+ reading.
So, I am confused about what to do now. Can someone please help me understand what is going wrong and how I can fix it. Thanks a lot, because I am stuck.

You have power but the scanner 'talks' to the PCM through the purple wire. Plug another scanner into the OBD-II port and see if it works. The schematics are a sticky in this section
'Special Schematics 2004-2008 Part 1'. Once it unzips, select 'Data Link Connector'.

[ZNA03]

Originally Posted by rtmsu_02

i have heard of that...the radio interferes with communications....when u get a tune, you should be asked to remove your radio fuse.....or at least every person i ever heard of has been asked.

You only need to remove the fuse if you have issues. If no issues you just make sure the radio is off then fire away.

[Canyon08Z71]

Originally Posted by ZNA03

You only need to remove the fuse if you have issues. If no issues you just make sure the radio is off then fire away.

Certain head unit adapters will cause the interference.

Service Bulletin: LAN/CAN comm. interference caused by after market radio harness

The above link will show you one of them to NEVER install on your Colorado or Canyon!

My guesstimation is along the same lines as the others stated... Something is jamming up the Readiness Tests in the PCM (if you are certain you have 12V to the ODBII plug). You need to find what is causing the interference, have a scan tool available to see the readiness test status.

[Slo86GT]

Nice link, never heard that before. I've got the Metra unit from Crutchfield, so I guess I'm in the clear.

[greg larkins]

wow, i've never heard about that before either. good thing too, because i just got my emissions testing done today. PASS. i guess that means i don't have the crappy interface module?

[southsidehustler]

I wanted to give you guys an update. I went back today, pulled the radio fuse and it worked. Thanks for the help everyone.

[ZNA03]

Originally Posted by southsidehustler

I wanted to give you guys an update. I went back today, pulled the radio fuse and it worked. Thanks for the help everyone.

Sweet!

[Kraco5]

I had the same prob. they told me either go get it fixed or they could test it the old fashion way. I told them check it the old fashion way cause their was nothing wrong with the truck.......sure enough I passed.