OBDII port not communicating

[dpnewfie]

Went to have the car inspected and it failed because the OBDII port was not communicating. Well, at least thats what the service guy told me. Any idea where to start for a fix to this problem?

Norm

[rogers9c1]

I had this problem on my 96 caprice I know the cars are years apart and not even the same styles but my cig lighter fuse was blown causing the odbII port to die with it, replace fuse scantool saw it, hope that helps. check your fuse's

[BlackHawk99]

Yep...had the exact same issue with our 97 Tahoe...ended up being the fuse for the cigarette lighter was blown, too. Check that fuse...the 05 might be the same story.

[wjcollier07]

Had the same problem in my 98 SE

I also concur, it was the cig lighter fuse.

[dpnewfie]

Didn't think to check that fuse because the cig lighter port still works. I have a radar detector pluged into it. I'm lost here all. However, I will take a look again when I get home tonight. Is there any way to check for power at the OBD plug?

Norm

[1fatcat]

Pin 4 is ground, pin 16 is battery voltage. Those two pins are power and ground for any OBDII car. Some of the other pins (discretionary) will vary from car to car.

[dpnewfie]

Awesome, thanks!

[1fatcat]

Remember, you need power AND ground to turn on the scan tool.

[dpnewfie]

So, what you are saying is I have to verify power at pin 16 as well as verify good ground at pins 4 and 5. Right?

[00Beast]

basically take your multimeter prongs (with the key on) and stick the black wire into the ground, and the red one into the power. If there's voltage, then it's time to look elsewhere.

[1fatcat]

Pin 5 is a signal ground, it is not used to power the scan tool so you do not need to check it. Be careful not to stretch the pin grips open when probing, you should just need to touch them with the probes.

[dpnewfie]

Great, thanks. I will get working on this as soon as I get home from work tonight. I'll keep you informed as to the outcome.

Norm

[dpnewfie]

Okay. I checked for power at the plug and everything was fine. Kept scratching my head as to what could be the problem. Anyway, finally decided to take it back to have the car re-tested and this time it passed. Apparently the service tech was an idiot.

Thanks all for the help!

Norm

[00Beast]

He probably hooked up the scanner up upside down. If it has a rubber plug, it's possible, as it won't work, but it'll seem like it's right, as there is the same amount of pins in each row. I did that at work one day with our snap-on scan tool. Took me 5 minutes to figure it out.

[dpnewfie]

I can see where it would be easy to do that. It was wrong of me to call the guy an idiot. I guess when you are doing a lot of these everyday mistakes will be made.

Again, thanks for the help.

[1965Bonneville]

I had this problem too (8/19/14). Symptoms: During the daytime, outside, the Dome lights do not come on - can't read the OBDII Port. Pull in the Gargage - it reads! No fuses blown. Relays are good too. My conclusion is this: When we had our Remote Start put on the car 18 months ago (professionally - by the BEST folks in town), I'm guessing that they changed something in the system.

So now, when I return for my New York State Safety Inspection Station during the daytime to simply confirm that the "Code / Error" has not returned (after 'the drive cycles' have completed), I simply stuff a towel on the Dashboard to cover the Daylight Photocell / Sensor & everyone's happy. Especially my wife;)