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Forum Gods - I've had an intermitted Check Engine Light for the last 2-3 months with a knock sensor code. I've reset it once with my Ancel analyzer tool, and it's gone off once before by itself. My battery faded about 3 weeks ago and I had to charge it overnight before the car would start. Since then, the check engine light came on again. I plugged in my scan tool and get a Communication fault now. It wont read the codes. I plugged the analyzer into my F150 and it works fine there. I took off the driver's kick panel to take a close look at the OBD2 plug, and the red and black leads to the OBD2 plug are spliced into as shown in the photo. I cant imagine that these splices are factory correct. I'm thinking that a previous owner was looking to power an accessory. Could this be the issue with the Comm fault??? Of course those splices have been there since I've owned the car. Thoughts? Thanks!
OBDII port does a straight shot wiring to the BCM. So could be the pins on the OBD II port that needs to be cleaned, could be the pins on the BCM connector side that needs to be cleaned, could be the scotch lock taps snapped the wires, or the splices up stream are grounding out, or could be a problem with the BCM.
As for the scotch lock wire taps, not factory, and would try to figure out what down line they are connected to in the first place.
I thought the OBD2 pin 6 and 14 were CAN buss and go to the computer (ECU not BCM). Mine won't inspect because they can't hook their scanner up. Autozone scan tool... same problem. I have a scan tool too and nada. Works fine on my BMW but not the vette! My car is a 2008 C6 and this has been an intermittent issue ever since I had the car. I reseated all 3 connectors on the BCM today to no avail. Next step is the computer I think? Anyone have any thoughts? Car runs perfect (NO CEL and car has 27K miles on it).
How many volts should I read with my Fluke 787 between 6 and 14?
I thought the OBD2 pin 6 and 14 were CAN buss and go to the computer (ECU not BCM). Mine won't inspect because they can't hook their scanner up. Autozone scan tool... same problem. I have a scan tool too and nada. Works fine on my BMW but not the vette! My car is a 2008 C6 and this has been an intermittent issue ever since I had the car. I reseated all 3 connectors on the BCM today to no avail. Next step is the computer I think? Anyone have any thoughts? Car runs perfect (NO CEL and car has 27K miles on it).
How many volts should I read with my Fluke 787 between 6 and 14?
You read resistance and not voltage “between” pins 6 and 14…it’s best to disconnect the battery when doing this but you will see 60 ohms…if you see 120 ohms you have issues !!…6 and 14 really don’t go just to the ECM because all those module are connected in parallel…now if you want to check voltage you would read terminal 6 (can high) to ground and see around 2.7 volts…pin 16 (can low) to ground you will see around 2.3 volts…it is best to see the CAN signals with a scope…basically it comes down to taking each module off the network until you can establish communication again with the scan tool!!…what kind of scan tool do you have and is it able to communicate with all the modules ??…also good idea to open a new thread with your concern…gets confusing with 2 threads going on here !!
OBD2 Comm failure
